http://repub.eur.nl/res/aut/9739/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/34999/ 2012-01-12T00:00:00Z Objective: The importance of genetic and environmental influences on children's behavioral and emotional problems may vary as a function of environmental exposure. We previously reported that 12-year-olds with divorced parents showed more internalizing and externalizing problems than children with married parents, and that externalizing problems in girls precede and predict later parental divorce. The aim of the current study was to investigate as to whether genetic and environmental influences on internalizing and externalizing problems were different for children from divorced versus non-divorced families. Methods: Maternal ratings on internalizing and externalizing problems were collected with the Child Behavior Checklist in 4,592 twin pairs at ages 3 and 12 years, of whom 367 pairs had experienced a parental divorce between these ages. Variance in internalizing and externalizing problems at ages 3 and 12 was analyzed with biometric models in which additive genetic and environmental effects were allowed to depend on parental divorce and sex. A difference in the contribution of genetic and environmental influences between divorced and non-divorced groups would constitute evidence for gene-environment interaction. Results: For both pre- and post-divorce internalizing and externalizing problems, the total variances were larger for children from divorced families, which was mainly due to higher environmental variances. As a consequence, heritabilities were lower for children from divorced families, and the relative contributions of environmental influences were higher. Conclusions: Environmental influences become more important in explaining variation in children's problem behaviors in the context of parental divorce. http://repub.eur.nl/res/pub/34907/ 2012-01-01T00:00:00Z Endophenotypes are intermediate phenotypes on the putative causal pathway from genotype to phenotype and can aid in discovering the genetic etiology of a disorder. There are currently very few suitable endophenotypes available for substance use disorders (SUD). The amplitude of the P300 event-related brain potential is a possible candidate. The present study determined whether the P300 amplitude fulfils two fundamental criteria for an endophenotype: (1) an association with the disorder (disease marker), and (2) presence in unaffected biological relatives of those who have the disorder (vulnerability marker). For this purpose, two separate meta-analyses were performed. Meta-analysis 1 investigated the P300 amplitude in relation to SUD in 39 studies and Meta-analysis 2 investigated P300 amplitude in relation to a family history (FH+) of SUD in 35 studies. The findings indicate that a reduced P300 amplitude is significantly associated with SUD (d=0.51) and, though to a lesser extent, with a FH+ of SUD (d=0.28). As a disease maker, the association between reduced P300 amplitude and SUD is significantly larger for participants that were exclusively recruited from treatment facilities (d=0.67) than by other methods (i.e., community samples and family studies; d=0.45 and 0.32, respectively), and larger for abstinent SUD patients (d=0.71) than for current substance users (d=0.37). Furthermore, in contrast to FH+ males, a P300 amplitude reduction seems not to be present in FH+ females (d=-0.07). Taken together, these results suggest that P300 amplitude reduction can be both a useful disease and vulnerability marker and is a promising neurobiological endophenotype for SUD, though only in males. Implications and future directions are discussed. http://repub.eur.nl/res/pub/34127/ 2011-12-01T00:00:00Z Aims: To study the prospective relationship between maternal smoking during pregnancy (MSP) and behavioral problems, heavy alcohol use, daily smoking, and ever use of cannabis in the offspring, and to assess the role of confounding and mediating factors in a systematic way. Methods: Population-based cohort study of 2,230 respondents, starting in 2001 when respondents were around the age of 11 years, and two follow-up measurements at intervals of about 2.5 years (response rates of 96.0 and 81.4%). Results: Almost one third of the respondents' mothers had smoked tobacco during pregnancy. These respondents were at an increased risk for all outcomes except internalizing problems (significant odds ratios ranged from 1.40 to 2.97). The successive models showed that the potential confounding factors reduced the strength of all relationships. In the full model, the strongest relationship was found for mothers who smoked more than 10 cigarettes a day during pregnancy and daily smoking in early adolescence (odds ratio: 1.56), but none of the relationships were statistically significant. Conclusions: MSP is a marker for future behavioral outcomes in the offspring, but reducing the prevalence of MSP is unlikely to make a meaningful contribution to the prevention of these problems in adolescents. Copyright http://repub.eur.nl/res/pub/33815/ 2011-11-01T00:00:00Z Background: The development of the fetal endocannabinoid receptor system may be vulnerable to maternal cannabis use during pregnancy and may produce long-term consequences in children. In this study, we aimed to determine the relationship between gestational cannabis use and childhood attention problems and aggressive behavior. Methods: Using a large general population birth cohort, we examined the associations between parental prenatal cannabis and tobacco use and childhood behavior problems at 18 months measured using the Child Behavior Checklist in N= 4077 children. Substance use was measured in early pregnancy. Results: Linear regression analyses demonstrated that gestational exposure to cannabis is associated with behavioral problems in early childhood but only in girls and only in the area of increased aggressive behavior (B= 2.02; 95% CI: 0.30-3.73; p= 0.02) and attention problems (B= 1.04; 95% CI: 0.46-1.62; p< 0.001). Furthermore, this study showed that long-term (but not short term) tobacco exposure was associated with behavioral problems in girls (B= 1.16; 95% CI: 0.20-2.12; p= 0.02). There was no association between cannabis use of the father and child behavior problems. Conclusions: Our results suggest that intrauterine exposure to cannabis is associated with an increased risk for aggressive behavior and attention problems as early as 18 months of age in girls, but not boys. Further research is needed to explore the association between prenatal cannabis exposure and child behavior at later ages. Our data support educating future mothers about the risk to their babies should they smoke cannabis during pregnancy. http://repub.eur.nl/res/pub/31020/ 2011-09-01T00:00:00Z Social skills (cooperation, assertion, and self-control) were assessed by teachers for a longitudinal cohort of (pre)adolescents, with measurements at average ages 11.1 (baseline) and 16.3 years (follow-up). Prospective associations with participants' self-reported use of cannabis, (age of) onset of cannabis use, and frequency of use at follow-up were examined using multinomial logistic regression analyses. Teacher-reported social skills predicted different aspects of cannabis use independent of better known factors such as presence of externalizing behavior and use of other substances. The direction of associations depended on the type of social skill. Good cooperation skills during early adolescence were associated with a reduced risk of lifetime cannabis use and a reduced risk of using cannabis on a regular basis. On the other hand, assertion at age 11 increased the risk of lifetime cannabis use and of using cannabis on an experimental basis. http://repub.eur.nl/res/pub/26637/ 2011-08-01T00:00:00Z Aims To investigate the relationship of life-time and repeated cannabis use with hypothalamic-pituitary-adrenal (HPA) axis reactivity to social stress in a general population sample of adolescents. Design Adolescents who reported life-time or repeated cannabis use, life-time or repeated tobacco use and never use of either cannabis or tobacco were compared with respect to their HPA axis reactivity during the Groningen Social Stress Task (GSST), which was based on the Trier Social Stress Task. Setting A large prospective population study of Dutch adolescents [the TRacking Adolescents' Individual Lives Survey (TRAILS) study]. Participants A total of 591 adolescents (51% male) who participated in the GSST, which was an additional measurement during the third assessment wave. Measurements HPA axis stress-reactivity was indexed by four cortisol samples collected before, during and after the GSST. Furthermore, all adolescents in our study completed self-reported questionnaires on life-time and repeated cannabis and tobacco use. Models were adjusted for sex, recent alcohol use, experimental session risk status, socio-economic status, mood and time of the experimental session. Findings Life-time cannabis users had significantly lower stress-reactivity levels when compared to abstainers [odds ratio (OR)=0.68, confidence interval (CI)=0.55-0.85, P<0.01] and life-time tobacco users (OR=0.79, CI=0.64-0.98, P<0.05). In addition, repeated cannabis users also exhibited lower stress-reactivity levels when compared to life-time ever users of either tobacco or cannabis (OR=0.74, CI=0.53-0.98, P<0.05). Conclusions Lower hypothalamic-pituitary-adrenal-axis stress-reactivity in adolescents is related specifically to life-time and repeated cannabis use. © 2011 The Authors, Addiction http://repub.eur.nl/res/pub/24036/ 2011-06-29T00:00:00Z The first aim of this study was to identify developmental trajectories of Attention Problems in twins followed from age 6 to 12 years. Second, we investigated whether singletons follow similar trajectories. Maternal longitudinal ratings on the Attention Problems (AP) subscale of the Child Behavior Checklist were obtained for a sample of 12,486 twins from the Netherlands Twin Register and for a general population sample of 1,346 singletons. Trajectories were analyzed by growth mixture modeling in twins, and compared with singletons. Teacher ratings on the AP subscale of the Teachers' Report Form were available for 7,179 twins and 1,211 singletons, and were used for cross-sectional mean comparisons at each age. All analyses were conducted for boys and girls separately. We identified three linear trajectories in both boys and girls, i.e., stable low (62-71%), low-increasing (15-18%), and high-decreasing (14-21%). Singletons followed three identical trajectories, with similar class proportions. Teacher ratings yielded no differences in mean levels of Attention Problems between twins and singletons. The development of Attention Problems from age 6 to 12 years can be characterized by stable low, low-increasing, and high-decreasing developmental trajectories. Twins and singletons are comparable with respect to the development of Attention Problems in childhood. http://repub.eur.nl/res/pub/26730/ 2011-06-01T00:00:00Z Background: The aim was to identify risk indicators from preadolescence (age period 10-12) that significantly predict unfavorable deviations from normal anxiety development throughout adolescence (age period 10-17 years). Methods: Anxiety symptoms were assessed in a community sample of 2,220 boys and girls at three time-points across a 5-year interval. Risk indicators were measured at baseline and include indicators from the child, family, and peer domain. Associations with anxiety were measured with multilevel growth curve analyses. Results: A stable difference in anxiety over adolescence was found between high and low levels of a range of child factors (frustration, effortful control), family factors (emotional warmth received from parents, lifetime parental internalizing problems), and peer factor (victims of bullying) ( P<.001). In contrast, the difference in anxiety between high and low levels of factors, such as self-competence, unfavorable parenting styles, and bully victims, decreased over adolescence ( P<.001). For other family factors, associations were weaker (.05<P<.001). Associations with parental education and family composition were not significant. Adjustment for concurrent depressive symptoms attenuated the associations, but those that were significant at P<.001 remained to be so. Specificity for anxiety subtypes (generalized anxiety, separation anxiety, social phobia, panic, and obsessive-compulsive symptoms) was reported for each association. Conclusions: Several child, family, and peer factors measured in preadolescence were risk indicators of high levels of anxiety symptoms throughout adolescence. Some factors (such as rejective parenting) were vulnerability indicators for anxiety in early adolescence only, whereas other factors (such as peer victimization) were indicators of long-term elevated anxiety levels. http://repub.eur.nl/res/pub/34385/ 2011-05-01T00:00:00Z Objective To unravel the mechanisms underlying the previously demonstrated associations between low birthweight and cardiovascular disease in adulthood, we examined whether maternal smoking during pregnancy leads to fetal arterial resistance adaptations, and subsequently to fetal growth retardation and changes in postnatal blood pressure and cardiac development. Design Prospective cohort study from early fetal life onwards. Setting Academic hospital. Population Analyses were based on 1120 children aged 2 years. Methods Maternal smoking during pregnancy [non-smoking, first trimester smoking, continued smoking (<5 and ≥5 cigarettes/day)] was assessed by questionnaire. Main outcome measures Third trimester placental and fetal arterial resistance indices and fetal growth were assessed by ultrasound and Doppler measurements. Postnatal blood pressure and cardiac structures (aortic root diameter, left atrial diameter, left ventricular mass) were measured at 2 years of age. Results First trimester smoking was not associated with third trimester placental and fetal blood flow adaptations. Continued smoking of ≥5 cigarettes/day was associated with an increased resistance in uterine, umbilical and middle cerebral arteries, and with a decreased flow and diameter of the ascending aorta. Among mothers who continued to smoke, the third trimester estimated fetal weights and birthweights were most affected in children with the highest umbilical artery resistance. Fetal arterial resistance indices were also associated with aortic root diameter and left atrial diameter. Conclusions Fetal arterial resistance adaptations may be involved in the pathways leading from maternal smoking during pregnancy to low birthweight and cardiovascular developmental changes in childhood in the offspring. http://repub.eur.nl/res/pub/25514/ 2011-04-01T00:00:00Z Objective: We examined to what extent internalizing and externalizing problems at age 3 preceded and predicted parental divorce, and if divorce and the time lapse since divorce were related to internalizing and externalizing problems at age 12. Methods: Parental ratings of internalizing and externalizing problems were collected with the Child Behavior Checklist (CBCL) in a large sample (N = 6,426) of 3-yearold children. All these children were followed through the age of 12 years, at which parents completed the CBCL again, while teachers completed the Teacher's Report Form. Children whose parents divorced between age 3 and age 12 were compared with children whose families remained intact. Results: Girls whose parents divorced between ages 3 and 12 already showed more externalizing problems at age 3 than girls whose parents stayed married. Higher levels of externalizing problems in girls at age 3 predicted later parental divorce. Parental reports indicated that 12-year-olds with divorced parents showed more internalizing and externalizing problems than children with married parents. Levels of teacher-reported problems were not different between children with married versus divorced parents. However, children whose parents divorced between ages 3 and 12 showed more teacher-rated internalizing problems at age 12 when the divorce was more recent than when the divorce was less recent. Parental ratings of both internalizing and externalizing problems at age 12 were not associated with the time lapse since divorce. Conclusion: Externalizing problems in girls precede and predict later parental divorce. Post-divorce problems in children vary by raters, and may depend on the time lapse since divorce. http://repub.eur.nl/res/pub/33492/ 2011-04-01T00:00:00Z The purpose of the present study was to investigate whether a length polymorphism in the dopamine receptor D4 gene (DRD4) was associated with approach related traits in adolescents. Data were used from TRAILS (TRacking Adolescents' Individual Lives Survey), a population based cohort of Dutch adolescents. Sensation seeking, assessed with personality questionnaires from the participants themselves and their biological father and mother (n=1282) was not associated with DRD4 genotype. Gambling performance (n=591) and startle reactivity (n=432) were not associated with DRD4 genotype either. Explanations for the dissociation might be sought in differences in development of the limbic system and the prefrontal cortex, both with high dopamine receptor D4 densities and both involved in approach related behaviours. http://repub.eur.nl/res/pub/34092/ 2011-04-01T00:00:00Z Psychologists, with their long-standing tradition of studying mechanistic processes, can make important contributions to further characterizing the risk associated with genes identified as influencing risk for psychiatric disorders. We report one such effort with respect to CHRM2, which codes for the cholinergic muscarinic 2 receptor and was of interest originally for its association with alcohol dependence. We tested for association between CHRM2 and prospectively measured externalizing behavior in a longitudinal, community-based sample of adolescents, as well as for moderation of this association by parental monitoring. We found evidence for an interaction in which the association between the genotype and externalizing behavior was stronger in environments with lower parental monitoring. There was also suggestion of a crossover effect, in which the genotype associated with the highest levels of externalizing behavior under low parental monitoring had the lowest levels of externalizing behavior at the extreme high end of parental monitoring. The difficulties involved in distinguishing mechanisms of gene-environment interaction are discussed. http://repub.eur.nl/res/pub/34260/ 2011-01-01T00:00:00Z Purpose There is substantial research linking tobacco and alcohol use to subsequent cannabis use, yet the specificity of this relationship is still under debate. The aim of this study was to examine which substance use modelthe gateway hypothesis, the common liability (CL) model and/or the route of administration modelbest explains the relationship between early onset of tobacco and alcohol use and subsequent cannabis use initiation. Methods We used data from 2,113 (51% female) Dutch adolescents who participated in three consecutive assessment waves (mean age: 11.09, 13.56, and 16.27 years, respectively) of the TRacking Adolescents' Individual Lives Survey study. (Pre)adolescent cannabis, tobacco and alcohol use was assessed using the Youth Self-Report and a TRacking Adolescents' Individual Lives Survey developed questionnaire. Results We found that, during adolescence, early onset of tobacco use does not pose a significantly higher risk of initiating cannabis use than early onset alcohol use. Therefore, we can rule out the route of administration model. Moreover, we found that adolescents who reported early onset comorbid use of both tobacco and alcohol have a higher likelihood to initiate cannabis use than adolescents who have tried either tobacco or alcohol. The gateway hypothesis is not broad enough to explain this finding. Therefore, the CL model best predicts our findings. Conclusion Future research on adolescent cannabis initiation should focus on testing the robustness of the CL model. Furthermore, identifying adolescents who use both tobacco and alcohol, before the age of 13, may help to curtail the onset of cannabis use. http://repub.eur.nl/res/pub/21837/ 2010-12-01T00:00:00Z Background Internalizing psychiatric disorders and early childhood adversity have both been associated with altered basal cortisol secretion. The aim of the present study is to investigate if early childhood adversity modifies the relationship between anxiety and mood disorders and cortisol secretion. Methods A sample of 429 international adoptees was followed from childhood to adulthood. In childhood, adoptive parents provided information about abuse and neglect before adoption. As adults, adoptees completed a standardized psychiatric interview to assess internalizing disorders and collected saliva samples four times a day. Analyses of covariance were performed. Results The relationship between anxiety disorders and cortisol secretion during 1 day, as measured by the area under the curve (AUC), was dependent on the experience of severe early maltreatment (p value of interaction = .03). In adoptees with an anxiety disorder, severe maltreatment was associated with lower daily cortisol secretion compared with nonmaltreated adoptees (respective AUC means: 28.19 and 36.96; difference = -8.78; confidence interval = -14.65 to -2.90; p = .004). In adoptees without an anxiety disorder, no difference in cortisol secretion was found between persons who did or did not experience severe maltreatment early in life (respective AUC means: 34.72 and 34.20; difference = .52; confidence interval = -1.92 to 2.96; p = .67). We found no modifying effect of severe early maltreatment on the relationship between mood disorders and daily cortisol secretion. Conclusions The experience of early adversities modifies the relationship between anxiety disorders and basal cortisol seretion in adults. To understand the relationship between anxiety disorders and cortisol secretion, early maltreatment has to be taken into account. http://repub.eur.nl/res/pub/28283/ 2010-12-01T00:00:00Z Aim: To verify self-reported information on prenatal drug use in urine because reporting in pregnancy is sensitive to stigma and might lead to misclassification. Methods: Using semiquantitative immunochemical analysis, the presence of the urinary metabolite (11-nor-Δ9-tetrahydrocannabinol- 9-carboxylic acid) was compared to self-reported prenatal cannabis use. Sensitivity and specificity for self-report and urinalysis outcomes were calculated and Yule's Y was used as an agreement measure. Results: Urine samples were available for 3,997 pregnant women. Of these women, 92 reported having used cannabis during pregnancy (2.3%) and 71 had positive urine screens (1.8%). In total 35% of the 92 women with self-reported cannabis use also had a positive urine screen. Positive urines were relatively frequent in women reporting cannabis use before pregnancy only (7.6%) and in women with missing information (2.6%). Sensitivity and specificity of urinalysis compared to self-report were 0.46 and 0.98. Sensitivity and specificity of self-report compared to urinalysis were 0.36 and 0.99. Yule's Y amounted to 0.77, indicating substantial agreement between the measures. Conclusions: Our findings illustrate the difficulties in obtaining valid information on prenatal cannabis use. To improve the quality of cannabis use data, we suggest a 2-step approach starting with self-report. Copyright http://repub.eur.nl/res/pub/27429/ 2010-10-01T00:00:00Z Objective: Our aim was to provide an overview of prospective studies that have addressed the association between attention problems (AP, i.e. symptoms of hyperactivity and inattentiveness) and academic achievement (AA). Method: We conducted a systematic search in the literature. Normal population studies and clinical studies were included. The methodological quality of each study was evaluated by objective criteria. A best evidence synthesis was used to determine the strengths of the association. Results: Sixteen studies were included. We found convincing evidence for a negative association between AP and AA. After controlling for intelligence, comorbidity, and socioeconomic status (SES), the association between the hyperactive symptoms of AP and AA was non-significant in two studies. Conclusion: Children with AP are at risk for lower AA and subsequent adverse outcomes later in life. Interventions in affected children should focus on their behavioural and educational development. http://repub.eur.nl/res/pub/20917/ 2010-09-01T00:00:00Z Background: Anxiety and depression might be two different valid constructs that often co-occur, or they could be different manifestations of the same underlying vulnerability. A theoretical framework to address this question is the tripartite model, by Clark and Watson, which hypothesizes that physiological hyperarousal (PH) is specific for anxiety. Knowledge about the relationship between PH, psychophysiological measures, perceived arousal, and anxiety would increase our understanding of the validity of the PH construct in this model. Our objective was to assess whether (a) hypothalamic-pituitary-adrenocortical (HPA) axis functioning, and (b) perceived arousal before, during and after stress can differentiate anxious from depressive children. Methods: In a general population sample of 225 children aged 8-12 years, self-reported anxiety and depressive symptoms were assessed using the Multidimensional Anxiety Scale for Children (MASC) and the Children's Depression Inventory (CDI). Perceived arousal was assessed using a self-report questionnaire before, during and after a stress task. Basal and reactive HPA-axis functioning were used as indices for psychophysiological arousal. Results: Our data showed that the relation between perceived arousal and anxiety problems is stronger than the relation with depressive problems. Reactive HPA-axis functioning is reduced in children with depressive problems. Conclusions: Some evidence was found in support of the tripartite model. Our findings indicate that perceived arousal to a challenge might be a useful tool to assess the PH component of the tripartite model. Reactive HPA-axis functioning might be able to differentiate between anxiety and depressive problems in children in a general population sample, but effect sizes are small and replication is needed. http://repub.eur.nl/res/pub/23065/ 2010-09-01T00:00:00Z The present study investigated whether autonomic flexibility predicted future anxiety levels in adolescent boys and girls. This study is part of the TRacking Adolescents' Individual Lives Survey (TRAILS), a prospective cohort study of Dutch adolescents. The current study included a subsample of 965 individuals. Measures of autonomic flexibility, i.e., heart rate (HR) and respiratory sinus arrhythmia (RSA), were determined during the first assessment wave (T1: participants 10–12 years old). Self-reported anxiety was assessed at the first and second assessment wave (T2: participants 12–14 years old). Possible gender differences and cooccurring depressive problems were examined. In girls, low RSA predicted anxiety levels 2 years later. In boys, no associations between HR and RSA and future anxiety were found. We conclude that in adolescent girls from the general population, signs of reduced autonomic flexibility (i.e., low RSA) predict future anxiety levels. Since the effect size was small, at this point, RSA reactivity alone cannot be used to identify individuals at risk for anxiety, but should be regarded as one factor within a large group of risk factors. However, if the present findings are replicated in clinical studies, intervention programmes – in the future – aimed at normalising autonomic functioning may be helpful. http://repub.eur.nl/res/pub/27959/ 2010-04-01T00:00:00Z Background: Cannabis is commonly used among pregnant women. It is unclear whether cannabis exposure causes hemodynamic modifications in the fetus, like tobacco does. Aims: This study aims to ascertain fetal blood redistribution due to intrauterine cannabis exposure. Methods: This study was embedded in the Generation R Focus Study, a population-based cohort of parents and children followed from pregnancy onwards. In late pregnancy, fetal hemodynamics was assessed with ultrasound measurements in cannabis-exposed and non-exposed fetuses. Pregnant women reported about substance use during pregnancy. A distinction was made between continued cannabis use (n=9), cannabis use only in early pregnancy (n=14), continued tobacco use (n=85), tobacco use only in early pregnancy (n=92), and no tobacco or cannabis use during pregnancy (n=85). Results: Continued cannabis use was associated with an increased pulsatility and resistance index of the uterine artery, while discontinued cannabis use was associated with a decreased pulsatility, and resistance index, as compared to controls. Additionally, continued cannabis exposure resulted in a significantly higher uterine pulsatility index and uterine resistance index compared to tobacco exposure. Continued cannabis use was found to be associated with a smaller aortic diameter, as well. No association between intrauterine cannabis exposure and the fetal cerebral vascular system was found. Conclusions: Our findings suggest that intrauterine cannabis exposure was associated with changes in hemodynamic programming of the vascular system of the fetus in late pregnancy mainly due to tobacco exposure, but intrauterine cannabis exposure did demonstrate a specific effect on the uterine blood flow. http://repub.eur.nl/res/pub/28134/ 2010-04-01T00:00:00Z Aims The aim of the present study was to determine the mediating role of affiliation with cannabis-using peers in the pathways from various dimensions of temperament to life-time cannabis use, and to determine if these associations also contributed to the development of regular cannabis use. Methods Objectives were studied using data from 1300 participants of the Tracking Adolescents' Individual Lives Survey (TRAILS), a large, general population study of Dutch adolescents. We used parent-reports on the Early Adolescent Temperament Questionnaire to assess the dimensions of high-intensity pleasure, shyness, fearfulness, frustration and effortful control at age 10-12 years. By means of self-reports, life-time and regular cannabis use were determined at age 15-18 years, and proportion of substance-using peers was determined at ages 12-15 and 15-18 years. Models were adjusted for age, sex, intelligence and parental cannabis use. Results High-intensity pleasure odds ratio (OR) = 1.09, 95% confidence interval (CI) = 1.05-1.13 and effortful control (OR = 0.92, 95% CI = 0.89-0.96) affected the risk for life-time cannabis use through their influence on affiliation with cannabis-using peers. Shyness affected this risk independently from peer cannabis use. Only the pathway from effortful control was associated additionally with the development of regular cannabis use (OR = 0.93, 95% CI = 0.89-0.98). Conclusions Peer cannabis use and, to a lesser extent, certain temperamental characteristics affect an adolescent's risk of cannabis use, and should be considered in prevention programmes. We recommend future research to focus upon factors that potentially modify the association between temperament, affiliation with cannabis-using peers and cannabis use. http://repub.eur.nl/res/pub/27374/ 2010-02-01T00:00:00Z Dysregulation of diurnal cortisol secretion patterns may explain the link between adversities early in life and later mental health problems. However, few studies have investigated the influence of social disadvantage and family adversity on the hypothalamic-pituitary-adrenal (HPA) axis early in life. In 366 infants aged 12-20 months from the Generation R Study, a population-based cohort from fetal life onwards, parents collected saliva samples from their infant at 5 moments over the course of 1 day. The area under the curve (AUC), the cortisol awakening response (CAR) and the diurnal cortisol slope were calculated as different composite measures of the diurnal cortisol rhythm. Information about social disadvantage and early adversity was collected using prenatal and postnatal questionnaires. We found that older infants showed lower AUC levels; moreover, infants with a positive CAR were significantly older. Both the AUC and the CAR were related to indicators of social disadvantage and early adversity. Infants of low income families, in comparison to high income families, showed higher AUC levels and a positive CAR. Infants of mothers who smoked during pregnancy were also significantly more likely to show a positive CAR. Furthermore, infants of mothers experiencing parenting stress showed higher AUC levels. The results of our study show that effects of social disadvantage and early adversity on the diurnal cortisol rhythm are already observable in infants. This may reflect the influence of early negative life events on early maturation of the HPA axis. http://repub.eur.nl/res/pub/33043/ 2010-02-01T00:00:00Z Research on twin-singleton differences in externalizing and internalizing problems in childhood is largely cross-sectional and yields contrasting results. The goal of this study was to compare developmental trajectories of externalizing and internalizing problems in 6- to 12-year-old twins and singletons. Child Behavior Checklist (CBCL) maternal reports of externalizing and internalizing problems were obtained for a sample of 9651 twins from the Netherlands Twin Register and for a representative general population sample of 1351 singletons. Latent growth modeling was applied to estimate growth curves for twins and singletons. Twin-singleton differences in the intercepts and slopes of the growth curves were examined. The developmental trajectories of externalizing problems showed a linear decrease over time, and were not significantly different for twins and singletons. Internalizing problems seem to develop similarly for twins and singletons up to age 9. After this age twins' internalizing symptoms start to decrease in comparison to those of singletons, resulting in less internalizing problems than singletons by the age of 12 years. Our findings confirm the generalizability of twin studies to singleton populations with regard to externalizing problems in middle and late childhood. The generalizability of studies on internalizing problems in early adolescence in twin samples should be addressed with care. Twinship may be a protective factor in the development of internalizing problems during early adolescence. http://repub.eur.nl/res/pub/21792/ 2010-01-01T00:00:00Z Aims: The aims of the present study were to determine the direct effect of DRD2 and DRD4, as well as their interaction with parenting (i.e. rejection, overprotection and emotional warmth), on the development of regular alcohol and cannabis use in 1192 Dutch adolescents from the general population. Methods: Information was obtained by self-report questionnaires. Perceived rejection, overprotection and emotional warmth were assessed at age 10-12. Regular alcohol and cannabis use were determined at age 15-18 and defined as the consumption of alcohol on 10 or more occasions in the past four weeks, and the use of cannabis on 4 or more occasions in the past four weeks. Models were adjusted for age, sex, parental alcohol or cannabis use, and externalizing behavior. Results: Carrying the A1 allele of the DRD2 TaqIA polymorphism, or the 7 repeat DRD4, was not directly related to regular alcohol or cannabis use. In addition, adolescent carriers of these genetic risk markers were not more susceptible to the influence of less optimal parenting. Main effects for parenting indicated that overprotection increased the risk of regular alcohol use, whereas the risk of cannabis use was enhanced by parental rejection and buffered by emotional warmth. Conclusions: Our findings do not support an association between DRD2/DRD4 and regular alcohol and cannabis use in adolescents. Given the substance-specific influences of rejection, overprotection and emotional warmth, these parenting factors might be promising candidates for prevention work. http://repub.eur.nl/res/pub/27743/ 2010-01-01T00:00:00Z Background: A returning dilemma for families with multiple births is whether twins should share the same, or a parallel classroom, or in other words, whether they should be separated at school or not. This study investigated the effects of sharing a classroom during primary school on cognitive achievement in twins. Method: Subjects were 839 monozygotic and 1164 dizygotic twin pairs who were registered at birth at The Netherlands Twin Register. A prospective, longitudinal study design was used with educational achievement at age 12 years, measured with a standardised test (CITO test), as outcome measure. Results: Most twin pairs (72%) shared a classroom during their schooling, 19% were in separate, but parallel, classes, and 9% "partly" shared a classroom. Twins who were in parallel classrooms had higher CITO scores (mean 539.51; SD 8.12), compared to twins who shared a classroom (537.99; SD 8.52). When controlling for socioeconomic status, and externalising problems before starting primary school (age 3), there was no significant difference in educational achievement between separated and non-separated twin pairs (p = 0.138). In addition, there was no interaction with sex or zygosity of the twins (p = 0.798). Conclusion: There is no difference in educational achievement between twins who share a classroom and twins who do not share a classroom during their primary school time. The choice of separation should be made by teachers, parents and their twin children, based on individual characteristics of a twin pair. http://repub.eur.nl/res/pub/27266/ 2009-12-16T00:00:00Z In order to establish the evidence for prospective relationships between temperamental and personality indicators of behavioral undercontrol and adolescent cannabis use, we systematically searched relevant papers published through April 2008. We assessed and evaluated 14 studies, of which only 4 were considered of high quality. Using "best evidence" synthesis, we found weak to moderate evidence for prospective relations between a combination of high approach and low avoidance and several measures of cannabis use. The study's limitations are noted. This review provides suggestions and recommendations for future studies in this area. Copyright http://repub.eur.nl/res/pub/17740/ 2009-11-01T00:00:00Z Aims We examined within a prospective longitudinal study whether cortisol levels were associated with smoking or drinking behaviours, taking parental substance use into account. Design The influence of parental substance use on cortisol levels of their adolescent offspring at age 10-12 years was examined. Next, cortisol levels of adolescents who initiated smoking or drinking at the first data collection (age 10-12) were compared to non-users. Finally, we examined whether cortisol levels could predict new onset and frequency of smoking and drinking 2 years later. Setting and participants First and second assessment data of the TRacking Adolescents' Individual Lives Survey (TRAILS) were used, including 1768 Dutch adolescents aged 10-12 years, who were followed-up across a period of 2 years. Measurements Cortisol was measured in saliva samples at awakening, 30 minutes later, and at 8 p.m. at age 10-12. Self-reported substance use at age 10-12 and 13-14, and parental self-reported substance use were used. Findings Only maternal substance use was related to slightly lower adolescent cortisol levels at 8 p.m. Both maternal and paternal substance use were associated with adolescent smoking and drinking at age 13-14, although fathers' use only predicted the amount used and not the chance of ever use. Finally, higher cortisol levels were related moderately to current smoking and future frequency of smoking, but not to alcohol use. Conclusions In a general population, parental heavy substance use does not seem to affect cortisol levels consistently in their offspring. We found some evidence for higher, instead of lower, hypothalamic-pituitary-adrenal axis activity as a predictor of smoking in early adolescence. http://repub.eur.nl/res/pub/24816/ 2009-10-01T00:00:00Z Background: Little is known about the development of anxiety symptoms from late childhood to late adolescence. The present study determined developmental trajectories of symptoms of separation anxiety disorder (SAD), social phobia (SoPh), generalized anxiety disorder (GAD), panic disorder (PD), and obsessive-compulsive disorder (OCD) in a large prospective community cohort. Methods: Anxiety symptoms were assessed in a community sample of 2220 boys and girls at three time-points across a 5-year interval. The Revised Child Anxiety and Depression Scale (RCADS) was used to assess anxiety symptoms, and multilevel growth-curve analyses were performed. Results: All subtypes of anxiety first showed a decrease in symptoms (beta for age ranged from -.05 to -. 13, p < .0001), followed by a leveling off of the decrease, and a subsequent slight increase in symptoms (beta for age-squared ranged from .006 to .01, p < .0001) from middle adolescence (GAD, SoPh, SAD) or late adolescence (PD and OCD) onwards. This increase in anxiety symptoms could not be explained by a co-occurring increase in depression symptoms. Girls had more anxiety symptoms than boys, and this difference remained stable during adolescence (p < .0001). Gender differences were strongly attenuated by adjustment for symptoms of depression. Conclusions: The current study shows that, in the general population, anxiety symptoms first decrease during early adolescence, and subsequently increase from middle to late adolescence. These findings extend our knowledge on the developmental course of anxiety symptoms during adolescence. This is the first study to separate the development of anxiety symptoms from that of symptoms of depression. http://repub.eur.nl/res/pub/24321/ 2009-09-01T00:00:00Z Background: While temperamental characteristics have been related to the onset of cannabis use, it is not clear at what point(s) along the trajectory from early onset of tobacco use (EOT) to early onset of cannabis use (EOC) these characteristics exert their impact. This study examined if (1) temperamental characteristics predispose to EOT that on its turn predisposes to EOC, and (2) temperament moderates the importance of EOT on the progression to EOC. Methods: Data from 1848 (83%) participants in the TRacking Adolescents' Individual Lives Survey (TRAILS), a prospective population study of Dutch adolescents, were analyzed. We used parent-reports on the Early Adolescent Temperament Questionnaire to assess the dimensions of high-intensity pleasure, frustration, effortful control, shyness and fearfulness at age 10-12. EOT and EOC were defined as use at least once before the ages of 12 and 13 years, respectively, assessed by means of self-reports. We performed mediation and moderation analyses in Mplus. Results: High levels of high-intensity pleasure predisposed to entrance in the trajectory from EOT to EOC. Once tobacco use had been initiated at early age, low levels of shyness and high levels of high-intensity pleasure increased the risk of progression to EOC. Conclusions: Besides a common liability for EOT and EOC based on temperament, the risk of transition from tobacco to cannabis use is modified by temperamental characteristics. Differences in interplay with other risk factors may explain the impact of temperament on distinct points along the substance use trajectory. http://repub.eur.nl/res/pub/24505/ 2009-09-01T00:00:00Z Interest in fetal origins of adverse offspring outcomes has grown extensively in the last decade. This has resulted in many published studies focusing on exposure in utero to substances and human offspring outcomes. Exposure to maternal substance use in pregnancy is believed to be a preventable hazard, and is therefore a main issue for public health concern and policy. However, an important question in human studies remains whether prenatal substance use exposure has an aetiological role in pathways to adverse developmental and behavioural outcomes via teratological effects. Recent insights and developments in research methodology will aid the adequate and more refined testing of associations between prenatal substance use and offspring outcomes. In particular, novel approaches could assist in disentangling the exposure to substance effects from correlated risk factors. The purpose of this manuscript is therefore to provide an overview of methodological issues involved in studies that focus on the association between maternal substance use during pregnancy and offspring's outcomes, to describe novel approaches to test these associations, and present some examples of new and well-designed studies and discuss their findings. http://repub.eur.nl/res/pub/24855/ 2009-09-01T00:00:00Z Objective: This study investigated whether baseline cortisol measures predicted future anxiety, and compared cortisol values of groups with different developmental pathways of anxiety. Method: Cortisol levels were assessed in 1768 individuals (10-12 years). Anxiety levels were assessed at the same age and 2 years later. Results: Cortisol measures did not predict future anxiety levels. Individuals with persistent anxiety problems did not show higher morning cortisol levels than those with persistently low, decreasing, or increasing anxiety levels. Instead, individuals with persistently high anxiety levels showed significantly lower evening cortisol levels than all other individuals. Further, participants with increasing anxiety levels showed higher morning cortisol levels (area under the curve; AUC) than individuals with persistently low anxiety levels. Conclusion: The extent to which the HPA-axis - by itself - plays a role in the aetiology of anxiety is questionable. Interactions of the HPA-axis with other biological or environmental factors may be more important. http://repub.eur.nl/res/pub/25203/ 2009-07-01T00:00:00Z Several studies found that maternal symptoms of anxiety or depression are related to functioning and development of the offspring. Within a population-based study of 2,724 children, we investigated the effect of maternal anxiety or depression on infant neuromotor development. Symptoms of anxiety and depression were measured during pregnancy and after giving birth; infant neuromotor development was assessed by trained research nurses during a home visit at the age of 3 months. The current study showed that mothers who were anxious during pregnancy had an elevated risk of having an infant with non-optimal neuromotor development. http://repub.eur.nl/res/pub/17768/ 2009-01-01T00:00:00Z Maternal internalizing problems affect reporting of child's problem behavior. This study addresses the relative effects of maternal depressive symptoms versus anxiety symptoms and the association with differential reporting of mother and child on child's internalizing problems. The study sample comprised a cohort of 1,986 10- to 12-year-old children and their mothers from the Dutch general population in a cross sectional setup. Children's internalizing problems were assessed with the DSM-IV anxiety and affective problem scales of the Child Behavior Checklist (CBCL) and the Youth Self-Report (YSR). Current maternal internalizing problems were assessed with the depressive and anxiety symptom scales of the Depression Anxiety Stress Scale (DASS), while the TRAILS Family History Interview (FHI) measured lifetime maternal depression and anxiety. Results show that current and lifetime maternal depressive symptoms were associated with positive mother-child reporting discrepancies (i.e. mothers reporting more problems than their child). Considering the small amount of variance explained, we conclude that maternal depressive symptoms do not bias maternal reporting on child's internalizing problems to a serious degree. Studies concerning long term consequences of mother-child reporting discrepancies on child's internalizing problems are few, but show a risk for adverse outcome. More prognostic research is needed. http://repub.eur.nl/res/pub/17770/ 2009-01-01T00:00:00Z For prevention of anxiety in children and adolescents, it is important to know whether family stress is a predictor of anxiety. We studied this in 1,875 adolescents from the Tracking Adolescents' Individual Lives Survey (TRAILS) who were followed up for 2 years, from age 10-12 to 12-14 years. Adolescents reported anxiety and depression symptoms at both assessments, and parents reported family stress (family dysfunction and parenting stress) at the first assessment. Family dysfunction was not associated with future anxiety, whereas high parenting stress was. Furthermore, family dysfunction was more strongly associated with anxiety than with depression, whereas parenting stress was more strongly associated with depression. Level of parental psychopathology explained part of the association of family stress with anxiety. The associations were modest and the understanding of the origins of adolescents' anxiety will require identifying other factors than family stress that account for more of the variance. http://repub.eur.nl/res/pub/29661/ 2008-12-15T00:00:00Z http://repub.eur.nl/res/pub/29746/ 2008-12-01T00:00:00Z Aims: To ascertain demographic, emotional and social determinants of cannabis use in early pregnancy. Design: This study was embedded in the Generation R study, a multiethnic population-based cohort of parents and their children, followed from pregnancy to childhood. Setting: Rotterdam, The Netherlands. Participants: Mothers enrolled in pregnancy who answered questions about their own and their partners substance use before and during pregnancy (n = 7610). Measurements: Using self-report questionnaires, information was collected on maternal demographics, psychopathology, delinquency, childhood trauma, social stress, family functioning, and parental alcohol, tobacco and substance use. Multinomial logistic regression analysis was used, with non-using women as reference. Findings: 246 (3.2%) women used cannabis before pregnancy and 220 (2.9%) women used cannabis both before and during pregnancy. The strongest determinant for maternal cannabis use during pregnancy was cannabis use by the biological father of the child (OR = 38.56; 95%CI = 26.14-58.88). Maternal cannabis use during pregnancy was also independently associated with being single (OR = 4.25; 95%CI = 2.33-7.75) or having a partner without being married (OR = 2.75; 95%CI = 1.56-4.85), childhood trauma (OR = 1.39; 95%CI = 1.22-1.57) and delinquency (OR = 3.37; 95%CI = 1.90-5.98), but not with maternal age, ethnicity, psychopathology, family functioning and perceived stress. Being religious was protective (Islam: OR = 0.25; 95%CI = 0.09-0.65) for maternal cannabis use during pregnancy. Additionally, lower educational level determined continued cannabis use in ever-users (OR = 3.22; 95%CI = 1.54-6.74). Conclusions: Our results showed that multiple demographic, emotional and social characteristics were associated with maternal cannabis use. These characteristics should be considered when investigating offspring exposed to cannabis in utero, as they may play an important role in mother-child interaction and child development. http://repub.eur.nl/res/pub/30137/ 2008-12-01T00:00:00Z Background/Aims: Symptoms of attention deficit hyperactivity disorder (ADHD) have often been associated with early-onset smoking. We hypothesize that reductions in ADHD symptoms due to an intervention have a mediating effect on early-onset smoking. Methods: In a universal, school-based, randomized controlled intervention trial, we examined whether intervention-induced reductions in ADHD symptoms at age 9 mediated the reduced risk of tobacco use onset among these children at age 10 or 11 years. A sample of 477 first-grade boys and girls were randomly assigned to the Good Behavior Game intervention (n = 263), a 2-year (grades 2 and 3) universal classroom-based intervention aimed at reducing disruptive behavior problems, or to a control condition (n = 214). ADHD symptoms were assessed through teacher ratings. Early onset of tobacco use was assessed through self-report. Results: The intervention-induced reductions in ADHD symptoms fully mediated the distal effect of intervention on reductions in early-onset smoking. Conclusions: Our results showed that programs that target ADHD symptoms may protect children from early-onset smoking as well. Further research is needed to examine pathways from ADHD symptoms to tobacco use. Copyright http://repub.eur.nl/res/pub/29581/ 2008-09-01T00:00:00Z Background: Although use of illicit drugs shows varying degree of heritability, the influence of shared and unique environmental factors predominate among adolescents. We explored factors predicting use of cannabis and other illicit drugs among Finnish adolescent twins. Methods: We used longitudinal data from the FinnTwin12-17 study with baseline at age 11-12 and follow-up at ages 14 and 171/2, including 4138 individuals. The outcome was self-reported ever use of cannabis or other illicit drugs at age 171/2. The potential predictors were measures reported by the twins, their parents or teachers. As individual factors we tested smoking, alcohol use, behavioral and emotional problems; as peer factors: number of smoking friends and acquaintances with drug experience; as family factors: parental substance use, socio-economic status and pre-natal exposure to nicotine. We used logistic regression models, controlling for twinship, age and sex, to compute odds ratios (OR) for each potential predictor. To adjust for within-family confounds, we conducted conditional logistic regressions among 246 twin pairs discordant for drug use. Results: 13.5% of subjects had initiated use of cannabis or other illicit drugs by age of 171/2. When adjusted for within-family confounds, smoking, drinking, and aggressiveness, as well as smoking and drug use among peers predicted use of illicit drugs. In the final regression model, the significant predictors were female sex, early smoking onset, drinking to intoxication, having smoking peers and acquaintances with drug experience, father's weekly drinking to intoxication, and aggressive behavior among boys. Smoking initiation by age of 12 was the most powerful predictor among individuals (OR = 26, p < 0.001) and within discordant pairs (OR = 22, p < 0.001). Conclusions: Early onset smoking is a powerful predictor for subsequent use of illicit drugs among Finnish adolescents, but the causal nature of this relationship needs to be clarified. http://repub.eur.nl/res/pub/29615/ 2008-09-01T00:00:00Z Persistent cigarette smoking is associated with significant morbidity and mortality. Correlates of difficulty quitting smoking include psychopathology, such as major depressive disorder, and problems with other substances, such as alcoholism. In addition, socio-demographic risk (e.g. poverty) and protective (e.g. living in a region with stringent tobacco laws) influences can modify risk for persistent cigarette smoking. Using data on 17,919 individuals with a lifetime history of smoking 100 or more cigarettes, from a nationally representative U.S. sample, we examine the constellation of risk and protective factors that correlate with smoking cessation (defined as remaining smoke-free in the past 12 months) across four cohorts: young (18-31 years), intermediate-aged (32-43 years), middle-aged (44-60 years) and older (61-99 years) adults. Using survival analyses, we demonstrate that in addition to a history of DSM-IV nicotine dependence, which is negatively associated with smoking cessation, living below the poverty line is also associated with persistent smoking across all age cohorts. Residents over the age of 31 years living on the U.S. West Coast are less likely to be persistent smokers as well. Major depressive disorder is associated with persistent smoking, but interestingly, only in middle-aged and older adults. Alcoholism and a family history of substance use problems are both correlated with persistent smoking but only in older adults. Here, we find evidence for psychopathology that may hinder successful quit attempts during the developmental period when a majority of quit attempts are made (early to mid-40's). However, our analyses also highlight the important benefits of effective tobacco legislation on the U.S. West Coast and urge policy makers to actively consider addressing issues surrounding tobacco taxation and the impact of poverty on tobacco use, in addition to the risks posed by co-occurring psychiatric problems and other substance use disorders. http://repub.eur.nl/res/pub/30263/ 2008-05-01T00:00:00Z Objectives. To examine the relationships between exposure to the air disaster in Amsterdam and multiple physical symptoms among firefighters and police officers, and to explore the role of post-traumatic stress symptoms (PTSS) herein. Design. Historic cohort study. Methods. On average 8.5 years post-disaster, exposed professional firefighters (N = 334) and police officers (N = 834) and their nonexposed colleagues (N = 194 and N = 634, respectively) completed questionnaires on disaster exposure and current symptoms. Logistic regression with adjustment for background characteristics was used to compare exposed and nonexposed workers. PTSS were added to these models, as was the interaction between exposure and PTSS, to explore potential mediating and modifying effects, respectively. Results. Exposed workers reported multiple physical symptoms significantly more often. Multiple physical symptoms seemed to have particularly affected the exposed firefighters who rescued people, and the exposed police officers who supported injured victims and workers, who were involved in the identification of or search for victims and human remains, who witnessed the immediate disaster scene or had a close one affected by the disaster. These exposure effects were essentially independent of PTSS, and no significant interactions between exposure and PTSS were found. Conclusions. In conclusion, the excess in post-disaster multiple physical symptoms in exposed workers could not be attributed to PTSS. http://repub.eur.nl/res/pub/28877/ 2008-04-01T00:00:00Z Objective: To determine the differential impact of maternal and paternal internalizing psychopathology on cognitive-behavioural treatment (CBT) outcome of anxiety-disordered children and adolescents. Method: Participants consisted of 127 children and 51 adolescents with a primary anxiety diagnosis. Children were randomly assigned to a standardized group CBT or individual CBT; adolescents received individual CBT. Parents received four training sessions. Participants were evaluated at pre- and post-treatment with a clinical interview and with self- and parent-reported questionnaires. Lifetime anxiety and mood disorders in parents were obtained with a clinical interview. Results: For children, no associations were found between maternal and paternal anxiety or mood disorders and treatment outcome. For adolescents, however, maternal lifetime anxiety disorders were positively associated with pre-post-treatment improvement in clinician severity ratings and with treatment success. Conclusion: Lifetime maternal anxiety disorders were significantly associated with favourable treatment outcomes in adolescents. Paternal disorders were not associated with treatment response. http://repub.eur.nl/res/pub/30214/ 2008-02-01T00:00:00Z This study examined the use of health care by police officers after the air disaster in Amsterdam. On average 8.5 years post-disaster, involved police officers (n = 834, who reported disaster-related tasks), and their non-involved colleagues (n = 634) completed questionnaires on disaster involvement and health care in the preceding 12 months. Logistic regression showed that involved police officers more often used drugs on their own initiative, sleeping pills or tranquillisers, and consulted a general practitioner or medical specialist, a paramedical specialist, and a privately practicing psychologist or psychiatrist. Thus, even after years, police officers involved in disaster work may use more self-initiated health care. http://repub.eur.nl/res/pub/30492/ 2008-02-01T00:00:00Z The aim of the present study was to estimate the genetic, shared and nonshared environmental contributions to self-reported and parent-reported internalizing and externalizing problems in a follow-up study of intercountry adopted young adults. Young Adult Self-Report ratings were obtained from 1475 adoptees aged 22-32 years and Young Adult Behavior Checklist ratings from 1115 adoptive parents. For the genetic analyses, a subset of 143 adopted biologically related and 295 unrelated siblings was used. The data were subjected to model fitting decomposing three sources of variance: genetic factors (A) shared environment (C) and nonshared environment (E). Genetic factors were of more importance in both self-reported (A2= 54%, C2= 0, and E2= 46%) and parent-reported (A2= 76%, C2= 15% and E2= 9%) internalizing problems. Environmental factors were of more importance in both self-reported (A2= 33%, C2= 17% and E2= 50%) and parent-reported (A2= 28%, C2= 27% and E2= 45%) externalizing problems. This was in contrast with findings from the first and second assessments in the same sample during adolescence when genetic factors were more important in explaining externalizing problems compared with internalizing problems. Our results suggest a developmental reversal in genetic and environmental influences on behavior problems from early adolescence into adulthood, which could be related to different underlying developmental trajectories. http://repub.eur.nl/res/pub/29986/ 2008-01-01T00:00:00Z Background. The Epidemiological Study Air Disaster in Amsterdam (ESADA) aimed to assess long-term health effects in professional assistance workers involved in the 1992 air disaster in Amsterdam. As part of ESADA indications of nephrotoxicity due to exposure to uranium from the balance weights of the crashed aircraft were assessed. Methods. Data of a historically defined cohort of 2499 (exposed and non-exposed) firefighters, police officers and hangar workers were collected 8.5 years after the disaster. Urinary uranium concentrations were determined by sector field inductively coupled plasma mass spectrometry. Urine albumin-creatinine ratio and fractional excretion of β2-microglobulin were calculated from a single-spot urine specimen and simultaneous blood sample. Exposed assistance workers were compared with their non-exposed colleagues, and associations between uranium and kidney function parameters were explored. Results. Median uranium concentrations were around 2 ng/g creatinine. Median values of albumin-creatinine ratio and fractional excretion of β2-microglobulin were well below the level for microalbuminuria and for tubular damage, respectively. No statistically significant differences between exposed and non-exposed workers were found in uranium concentrations and kidney function parameters, although exposed hangar workers had lower uranium concentrations. No statistically significant associations were found between uranium concentrations and kidney function parameters in the total cohort. Conclusions. Occupational exposure to the air disaster in Amsterdam was neither significantly associated with higher uranium concentrations, nor with disturbed kidney function parameters. In this large cohort of professional assistance workers, urinary uranium concentrations were in the low range compared with previously published reference populations. No indications of nephrotoxicity were found at urinary uranium concentrations around 2 ng/g creatinine. http://repub.eur.nl/res/pub/35072/ 2007-12-01T00:00:00Z Objective: Research in animals has shown that exposure to stressors during pregnancy is associated with offspring behavioural disorders. We aimed to study the effect of in utero exposure to the Chernobyl disaster in 1986, and maternal anxiety presumably associated with that exposure, on behaviour disorder observed at age 14. Method: Exposed (n = 232) and non-exposed Finnish twins (n = 572) were compared. A semi-structured interview was used to assess lifetime symptoms of depression, generalized anxiety disorder, attention deficit hyperactivity disorder, conduct disorder and oppositional defiant disorder symptoms. Results: Adolescents who were exposed from the second trimester in pregnancy onwards, had a 2.32-fold risk (95% CI: 1.13-4.72) of having lifetime depression symptoms, an increased risk of fulfilling DSM-III-R criteria of a major depressive disorder (OR = 2.48, 95% CI: 1.06-5.7), and a 2.01-fold risk (95% CI: 1.14-3.52) of having attention deficit hyperactivity disorder symptoms. Conclusion: Perturbations in fetal brain development during the second trimester may be associated with the increased prevalence of depressive and attention deficit hyperactivity disorder symptoms. http://repub.eur.nl/res/pub/35793/ 2007-06-01T00:00:00Z The aim of this study was to test for sex differences in the role of physical and relational victimization in anxiety and depression development through a randomized prevention trial. 448 seven-year-old boys and girls were randomly assigned to the Good Behavior Game intervention, a two-year universal classroom based intervention aimed at reducing disruptive behavior problems and creating a safe and predictable classroom environment, or to a control condition. Assessments of self-reported physical and relational victimization at age 10 years, and self-reported major depressive disorder, generalized anxiety, social anxiety, and panic/agoraphobia symptoms at age 13 years were available. Reductions in anxiety/depression were mediated by reduced rates of relational victimization in girls, whereas reductions in physical victimization accounted for the reduced anxiety/depression scores among boys. The results support sex-specific pathways of victimization leading to anxiety and depression. http://repub.eur.nl/res/pub/36456/ 2007-06-01T00:00:00Z http://repub.eur.nl/res/pub/36499/ 2007-03-01T00:00:00Z Background: In 1992 a cargo aircraft crashed into apartment buildings in Amsterdam. In the troublesome aftermath rumours emerged on potential toxic exposures and health consequences. The aim of this study is to assess the long-term impact of this disaster on the health-related quality of life (HRQoL) of professional assistance workers. Methods: Historic cohort study, using questionnaires to assess occupational disaster exposure, HRQoL (SF36), and background variables, at on average 8.5 years post-disaster. Participating were the exposed professional firefighters (n = 334) and police officers (n = 834) who reported disaster-related task(s), and their non-exposed colleagues who did not report such tasks (n = 194, and n = 634, respectively). Results: Multivariate logistic regression analysis showed that exposed workers reported a significantly lower physical HRQoL and vitality than non-exposed workers. Exposed police officers also reported a lower mental HRQoL. Among exposed workers, a lower HRQoL was reported significantly more often by workers who had a close one affected by the disaster; by firefighters who rescued people, cleaned-up, or witnessed the immediate disaster scene; and by police officers who supported the injured. Exposed police officers who perceived the disaster as 'not bad' reported a lower HRQoL less often than those to whom it was 'the worst ever'. Conclusions: This study demonstrates that professional disaster assistance workers are at risk for a lower HRQoL, even after years. http://repub.eur.nl/res/pub/35673/ 2007-01-01T00:00:00Z This study examined specific and general psychological distress 8.5 years following the 1992 cargo aircraft crash in Amsterdam. Participants included 334 occupationally exposed fire fighters and 834 occupationally exposed police officers compared with reference groups of 194 fire fighters and 634 police officers who were exposed to duty-related stressors other than the disaster. On the standardized instruments of psychological distress, exposed fire fighters reported more somatic complaints and fatigue, while exposed police officers reported higher psychological distress on all aspects. The degree and type of exposure at the disaster site and other background factors were associated with several outcomes of psychological distress levels of exposed rescue workers. The disasters' aftermath of rumors about potential health consequences due to toxic exposure likely contributed to the long-lasting psychological distress of some of the rescue workers as well. http://repub.eur.nl/res/pub/8259/ 2006-01-01T00:00:00Z OBJECTIVE: To investigate whether using ecstasy (3,4-methylenedioxymethamphetamine, MDMA) is preceded by symptoms of behavioural and emotional problems in childhood and early adolescence. DESIGN: Prospective, longitudinal, population based study SETTING: The Dutch province of Zuid-Holland. PARTICIPANTS: A sample of 1580 individuals, followed up across a 14 year period, from childhood into adulthood. MAIN OUTCOME MEASURES: The first assessment took place in 1983 before MDMA appeared as a recreational drug in the Netherlands and included the child behaviour checklist to obtain standardised parents' reports of their children's behavioural and emotional problems. Use of the drug was assessed with the composite international diagnostic interview 14 years later. RESULTS: Eight syndrome scales of childhood behaviour were examined. Scores in the deviant range for the scales designated as anxious or depressed in childhood were significantly related to use of MDMA in adolescents and adults, resulting in an increased risk (hazard ratio 2.22, 95% confidence interval 1.20 to 4.11, P = 0.01). CONCLUSIONS: Individuals with childhood symptoms of anxiety and depression may have an increased tendency to use MDMA in adolescence or young adulthood. Its effects are supposed to include enhanced feelings of bonding with other people, euphoria, or relaxation. Especially individuals with symptoms of anxiety or depression may be susceptible to these positive effects.