Thought suppression in obsessive-compulsive disorder.

Social cognition research has indicated that attempts to suppress thoughts can lead to a paradoxical increase in the frequency of that thought. This phenomenon has been a central component of cognitive-behavioural models of obsessive-compulsive disorder (OCD); however, research has yet to demonstrate deficient thought suppression ability in OCD patients. We examined whether individuals with OCD (OCs) exhibit a deficit in the ability to suppress thoughts. In Experiment 1, attempted thought suppression led to a paradoxical increase in self-reported thoughts for OCs, but not for nonanxious controls (NACs) or anxious controls (ACs). In order to rule out self-report biases, in Experiment 2 we utilized a lexical decision paradigm that measured priming strength of a target word under thought suppression conditions. Results paralleled those of Experiment 1: OCs showed decreased lexical decision latency of the 'suppressed' thought (thought to reflect either increased priming strength or disrupted processing of nonsuppressed thoughts), thus exhibiting a paradoxical effect of thought suppression. This effect was not seen in NACs or ACs. These findings suggest that deficits in cognitive inhibitory processes may underlie the intrusive, repetitive nature of clinical obsessions.