Heiden, C. van der

disorder patient anxiety treatment anxiety disorder factor sample model study symptom therapy belief problem chapter result penn state gad patients effect questionnaire version heiden community sample journal research score van der measure anxiety disorders metacognition uncertainty community worry outcome group borkovec metacognitive dutch version intolerance state vulnerability dutch depression criteria ladouceur strategy neuroticism event condition difference process vulnerability factors behaviour research diagnosis van der heiden metacognitive therapy table method scale relationship participant uncertainty intolerance psychology follow-up control assessment situation practice posttreatment jerry depressive trial structure intolerance-of-uncertainty therapy depressive symptoms one-factor behavior behaviour solution psychiatry example