Relationship between social-cognitive and social-perceptual aspects of theory of mind and neurocognitive deficits, insight level and schizotypal traits in obsessive-compulsive disorder.

OBJECTIVE: The primary aim of the current study was to investigate different aspects of theory of mind (ToM), including social-cognitive (ToM-reasoning) and social-perceptual (ToM-decoding) in obsessive-compulsive disorder (OCD). We also aimed to investigate the relationship between ToM, neurocognition and a number of clinical variables including overvalued ideas, schizotypal personality traits, level of insight, and disease severity.

METHOD: Thirty-four patients who have been diagnosed with OCD according to DSM-IV and 30 healthy controls were included in the study. All participants were given a neuropsychological battery including tasks measuring ToM-reasoning, ToM-decoding and other neurocognitive functions. Schizotypal Personality Questionnaire (SPQ), Yale Brown Obsession and Compulsion Scale (YBOC-S) and Overvalued Ideas Scale (OVIS) were also administered to the participants.

RESULTS: Patients with OCD showed significant deficits in both aspects of ToM. ToM performances of patients showed a significant positive correlation with neurocognitive functions. When controlled for general cognition factor, patient-control difference for ToM-reasoning (F = 3,917; p = 0,05), but not ToM-decoding, remained statistically significant. ToM-reasoning impairment of patients was significantly related to the severity of OCD symptoms and poor insight (p = 0,026 and p = 0,045, respectively). On the other hand, general cognitive factor (β = 0,778; t = 3,146; p = 0,04) was found to be the only significant predictor of ToM-reasoning in OCD patients in the multiple linear regression model.

CONCLUSION: OCD is associated with ToM impairment, which is related to schizotypal traits, disease severity and poor insight, yet neurocognitive deficits also significantly contribute to this finding. However, ToM-reasoning impairment could be considered as a relatively distinct feature of OCD, which is partly separate from general cognitive deficits.