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Background Several lines of research suggest that prefrontal cortex dysfunctions observed in obsessive compulsive disorder (OCD) and schizophrenia (SKZ) are linked to two partially independent neuroanatomic systems: the ventromedial prefrontal cortex and the dorsolateral prefrontal cortex, with different neuroanatomic connections, including the striatum. The primary aim of this study was to test this hypothesis using a double dissociation study of neuropsychological tasks performance of the dorsolateral prefrontal cortex and ventromedial prefrontal cortex. Methods We administered the Wisconsin Card Sorting Test, the Gambling Task, and the four-disk version of the Tower of Hanoi to 110 SKZ and 67 OCD patients and 56 control subjects. Results A clear double dissociation of Wisconsin Card Sorting Test and Gambling Task performances was found, with SKZ patients performing the Wisconsin Card Sorting test significantly worse than OCD patients and control subjects and OCD patients performing the Gambling Task significantly worse than SKZ and control subjects. Both SKZ and OCD patients performed the Tower of Hanoi significantly worse than control subjects. Conclusions Results from our double dissociation study confirm the hypothesis of involvement of different frontal lobe subsystems within basal–corticofrontal circuits function in SKZ and OCD.

Background Evidence in literature suggests that neurocognitive deficits may represent suitable intermediate-phenotype candidates for the dissection of obsessive-compulsive disorder (OCD) genetic heterogeneity. The aim of this study was to search for possible OCD neurocognitive endophenotypes by assessing decision-making, planning, and mental flexibility profiles in OCD probands, healthy control subjects (HC), and their respective relatives. Methods The sample consisted of 35 pairs of OCD probands without other Axis I comorbidities and unaffected first-degree relatives and 31 pairs of HC subjects without a known family history of OCD and their relatives. Neuropsychological assessment was performed using the Iowa Gambling Task (IGT), the Tower of Hanoi (ToH), and the Wisconsin Card Sorting Test (WCST). Results Obsessive-compulsive disorder patients showed impairments in decision making, planning, and mental flexibility, given that OCD probands performed significantly poorer than HC probands at the IGT, the ToH, and the WCST. Obsessive-compulsive disorder relatives performed poorer at these tests than HC probands and relatives. Symptom severity was found to have no influence on neurocognitive performance. Analysis of proband/relative concordance in task performance was performed for each task. A significant overall difference was found when comparing the percentages of the different concordance profiles of our OCD and HC samples with regard to IGT and ToH performance. No significant difference was found in the WCST. Conclusions Executive dysfunctions may qualify as a suitable endophenotype candidate for OCD. Concordance rates in neuropsychological task performance suggest that decision-making and planning deficits aggregate in these families and therefore might be a heritable component of OCD.

Several lines of research suggest that prefrontal cortex dysfunctions observed in obsessive compulsive disorder (OCD) and schizophrenia (SKZ) are linked to two partially independent neuroanatomic systems: the ventromedial prefrontal cortex and the dorsolateral prefrontal cortex, with different neuroanatomic connections, including the striatum. The primary aim of this study was to test this hypothesis using a double dissociation study of neuropsychological tasks performance of the dorsolateral prefrontal cortex and ventromedial prefrontal cortex.We administered the Wisconsin Card Sorting Test, the Gambling Task, and the four-disk version of the Tower of Hanoi to 110 SKZ and 67 OCD patients and 56 control subjects.A clear double dissociation of Wisconsin Card Sorting Test and Gambling Task performances was found, with SKZ patients performing the Wisconsin Card Sorting test significantly worse than OCD patients and control subjects and OCD patients performing the Gambling Task significantly worse than SKZ and control subjects. Both SKZ and OCD patients performed the Tower of Hanoi significantly worse than control subjects.Results from our double dissociation study confirm the hypothesis of involvement of different frontal lobe subsystems within basal-corticofrontal circuits function in SKZ and OCD.