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Fronto‐temporal function may distinguish bipolar disorder from schizophrenia
Author(s) -
Frangou S,
Dakhil N,
Landau S,
Kumari V
Publication year - 2006
Publication title -
bipolar disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.285
H-Index - 129
eISSN - 1399-5618
pISSN - 1398-5647
DOI - 10.1111/j.1399-5618.2006.00274.x
Subject(s) - stroop effect , psychology , wisconsin card sorting test , verbal fluency test , schizophrenia (object oriented programming) , bipolar disorder , cognition , audiology , neuropsychology , prefrontal cortex , psychosis , bipolar i disorder , neuroscience , cognitive psychology , psychiatry , mania , medicine
Objectives: There is evidence for differential neural alterations within the prefrontal cortex (PFC) in bipolar disorder I (BDI) and schizophrenia that may translate into different cognitive deficits. Our objective was to compare the cognitive profile of stable BDI and schizophrenic patients using neuropsychological tasks which utilize frontal systems but differ in terms of the exact neural circuits and cognitive processes involved. Methods: We studied 43 patients with BDI, 54 with schizophrenia and 46 matched healthy participants. All participants completed (i) the Wisconsin Card Sorting Test (WCST) which is known to recruit the dorsal and ventral PFC, (ii) the verbal fluency task (VFT), which engages frontal‐temporal regions, and (iii) the Stroop Colour Word Test (SWCT) which depends on the integrity of the cingulo‐frontal network. A series of multivariate analyses examined differences between the cognitive profiles of BD and schizophrenic patients relative to that of healthy participants controlling for general intellectual ability and gender. Results: Bipolar disorder I patients showed minimal verbal fluency impairment while schizophrenic patients demonstrated marked deficits on this task relative to the control and BDI groups. The two patient groups had comparable performance on the WCST. In the SWCT, schizophrenic patients showed impairment in both congruent and incongruent conditions while BD patients had deficits only in the latter. Conclusions: Absence of significant verbal fluency abnormalities and by inference dysfunction in the associated fronto‐temporal circuitry may distinguish BDI from schizophrenia. Both disorders may show impairment in tasks involving cingulo‐frontal networks with evidence of greater cingulate dysfunction in schizophrenia.