Cognitive performance and specific deficits in OCD symptom dimensions: I.Olfactory perception and impaired recognition of disgust

Objective: To investigate the ability of patients with obsessive-compulsive disorder (OCD) in identifying pleasant and disgusting smells. Methods: Participants were 55 OCD patients and 80 healthy controls, also matched for history of cigarette smoking. They were administered a smell identification test consisting of a subsample of 13 smells from the Pennsylvania Smell Identification Test (UPSIT) in addition to two new smells. Participants were exposed to smells from liquids in glass bottles. Results: The OCD patients were significantly impaired compared to the healthy controls in identifying the smells. When controlling for anxiety, this group difference remained stable only for disgusting but not pleasant smells. An effect of patients in different symptom dimensions on smell identification was also found. Conclusion: These findings suggest that in OCD, a specific dysfunction related to emotional appraisal of sensory stimuli, in the absence of a sensory deficit, may be apparent. This emotional deficiency could stem from disruption in processing related to the orbitofrontal cortex (OFC).