Marital status is associated with all kinds of health outcomes: both subjective health states (illness, e.g., self-perceived health) and objective health states (disease, e.g., clinically diagnosed conditions), both mental and physical health, and both morbidity and mortality. Health differences between marital status groups are generally assumed to result from both an effect of health on marital status (selection) and an effect of marital status on health (social causation). Marital status affects health through several intermediary factors; of these, psychosocial factors, especially psychosocial stress, occupy a central position.