Impact of coexistent schizotypal personality traits on frontal lobe function in obsessive–compulsive disorder

Objective This study was a post-hoc analysis of the results from a neuropsychological battery which was conducted to investigate the frontal lobe difference between obsessive–compulsive disorder (OCD) patients with and without schizotypal personality trait (SPT), especially dorsolateral prefrontal and medial frontal functions. Methods Fifty-five OCD patients were divided into two groups according to their Personality Disorder Questionnaire-4+ scores. Patients with OCD with SPT ( n = 17) and OCD without SPT ( n = 38) were compared to 52 schizophrenia patients and 67 healthy subjects. Two neuropsychological tasks, the Wisconsin Card Sorting Test (WCST) and verbal fluency tests which are considered to reflect dorsolateral and medial frontal functions, were selected for an analysis. Results OCD with SPT patients and patients with schizophrenia performed significantly worse than controls in both the WCST and verbal fluency tasks, whereas OCD without SPT patients showed no deficits in the same tasks. Moreover, we found no statistically significant difference in either task between patients having OCD with SPT and patients with schizophrenia. Conclusion This study indicate that OCD with SPT may have distinct patterns of neurocognitive deficit that differ from those of OCD without SPT, especially in terms of frontal lobe function.