Background: Recent evidence suggests that obsessive-compulsive disorder (OCD) and Tourette's disorder are related and have overlapping clinical features. The purpose of this study was to test the following hypotheses regarding intentional repetitive behaviors in these two disorders: (1) In OCD without comorbid Tourette's, they are preceded by cognitive phenomena and autonomic anxiety, but not sensory phenomena, and (2) in Tourette's without comorbid OCD, they are preceded by sensory phenomena, but not cognitive phenomena nor autonomic anxiety.
Method: Fifteen adult OCD outpatients without tics and 17 adult Tourette's outpatients without OCD were evaluated with a structured interview. Questions assessed cognitive, sensory, and affective experiences related to intentional repetitive behaviors.
Results: Five of 17 Tourette's subjects were excluded because they had only unintentional or occasionally intentional tics. All OCD patients reported some cognitions preceding their intentional repetitive behaviors, whereas only 2 of 12 Tourette's patients reported cognitions. In comparison, all Tourette's patients reported sensory phenomena preceding repetitive behaviors, and none of the OCD patients reported such sensations. In addition, 13 OCD patients reported at least mild autonomic anxiety associated with their repetitive behaviors, whereas no Tourette's patients reported such symptoms.
Conclusion: Intentional repetitive behaviors in OCD differ from those in Tourette's and are associated with cognitive and autonomic phenomena. Sensory phenomena preceded intentional repetitive behaviors in Tourette's but not in OCD patients. The dimensions examined in this study (cognition, sensory phenomena, and autonomic anxiety) may represent valid clinical factors for characterization of repetitive behaviors in OCD and Tourette's.