Obsessive-compulsive symptoms, obsessive-compulsive disorder, and related disorders in Parkinson's disease.

This study evaluated the frequency of obsessive-compulsive disorder (OCD), obsessive-compulsive symptoms (OCS), and related disorders (e.g., tic disorders, trichotillomania, and body dysmorphic disorder) in 100 patients with Parkinson's disease (PD) and 100 individually matched controls. When compared with controls, OCD, OCS, and related disorders were not higher in PD. Findings revealed an association of some OCS with left side motor symptom predominance in PD patients, particularly for symmetry and ordering/arranging. These findings suggest that the right hemisphere likely functions in the expression of OCS.