Symptom dimensions are associated with age of onset and clinical course of obsessive-compulsive disorder.

Meta-analysis of the heterogeneous symptoms of obsessive-compulsive disorder (OCD) has found a four-factor structure of symptom dimensions consisting of cleaning, forbidden thoughts, symmetry, and hoarding. Research into age of onset of symptom dimensions has yielded inconsistent results, and it is unknown whether symptoms along these dimensions differ in their clinical course. We assessed age of onset and clinical course of different OCD symptom dimensions in a large cohort of adult patients. Nine-hundred fifty-five subjects were assessed using the Dimensional Yale-Brown Obsessive-Compulsive Scale. For age of onset analysis, we tested across three methods of classification: (1) primary (more severe) symptom dimension (2) clinically significant symptoms within a dimension or (3) any symptoms within a dimension. Age of onset was defined as the earliest age of onset reported for any individual item within a symptom dimension. For analysis of different types of clinical course, we used chi-square tests to assess for differences between primary symptom dimensions. OCD symptoms in the symmetry dimension had an earlier age of onset than other OCD symptom dimensions. These findings remained significant across all three methods of classification and controlling for gender and comorbid tics. No significant differences were found between the other dimensions. Subjects with primary OCD symptoms in the forbidden thoughts dimension were more likely to report a waxing-and-waning course, whereas symmetry symptoms were less likely to be associated with a waxing-and-waning course.