Biopsychosocial etiology of obsessions and compulsions: an integrated behavioral-genetic and cognitive-behavioral...

Accumulating evidence suggests that particular kinds of dysfunctional beliefs contribute to obsessive-compulsive (OC) symptoms. Three domains of beliefs have been identified: (a) perfectionism and intolerance of uncertainty, (b) overimportance of thoughts and the need to control thoughts, and (c) inflated responsibility and overestimation of threat. These beliefs and OC symptoms are both heritable. Although it is widely acknowledged that OC symptoms probably have a complex biopsychosocial etiology, to our knowledge there has been no previous attempt to integrate dysfunctional beliefs and genetic factors into a unified, empirically supported model. The present study was an initial step in that direction. A community sample of monozygotic and dizygotic twins (N = 307 pairs) completed measures of dysfunctional beliefs and OC symptoms. Structural equation modeling was used to compare 3 models: (a) the belief causation model, in which genetic and environmental factors influence beliefs and OC symptoms, and beliefs also influence symptoms; (b) the symptom causation model, which is the same as (a) except that symptoms cause beliefs; and (c) the belief coeffect model, in which beliefs and OC symptoms are the product of common genetic and environmental factors, and beliefs have no causal influence on symptoms. The belief causation model was the best fitting model. Beliefs accounted for a mean of 18% of phenotypic variance in OC symptoms. Genetic and environmental factors, respectively, accounted for an additional 36% and 47% of phenotypic variance. The results suggest that further biopsychosocial investigations may be fruitful for unraveling the etiology of obsessions and compulsions.