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Neuropsychological deficits and functional impairment in bipolar depression, hypomania and euthymia
Author(s) -
Malhi Gin S,
Ivanovski Belinda,
HadziPavlovic Dusan,
Mitchell Philip B,
Vieta Eduard,
Sachdev Perminder
Publication year - 2007
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.1399-5618.2007.00324.x
Subject(s) - hypomania , bipolar disorder , psychology , verbal memory , neuropsychology , bipolar ii disorder , mania , neurocognitive , psychiatry , executive functions , depression (economics) , clinical psychology , verbal fluency test , bipolar i disorder , cognition , audiology , medicine , economics , macroeconomics
Objective: To examine whether patients with bipolar disorder (BD) have subtle neuropsychological deficits that manifest clinically as cognitive and functional compromise, and this study attempted to determine the pattern of such cognitive deficits and their functional impact across all three phases of BD. We hypothesised that euthymia does not equate with normal neuropsychological function and that each phase has a characteristic pattern of deficits, with disturbance in attention and memory being common across all phases of the illness: (i) bipolar depression – psychomotor slowing and impairment of memory; (ii) hypomania by frontal‐executive deficits and (iii) euthymia – a mild disturbance of attention, memory and executive function. Methods: Twenty‐five patients with a diagnosis of bipolar I disorder underwent neuropsychological testing over a period of 30 months in the natural course of their illness while hypomanic and/or depressed and/or euthymic. The results from these assessments were compared with findings from neuropsychological tests conducted on 25 healthy controls matched for age, sex, education and handedness. Results: Initial analyses revealed modest impairment in executive functioning, memory and attention in both hypomanic and depressed bipolar patients, with additional fine motor skills impairment in the latter. Memory deficits, also noted in euthymic patients, were non‐significant after controlling for confounding variables, although bipolar depressed patients remained significantly impaired on tests of verbal recall. Bipolar depressed and hypomanic patients differed with respect to the nature of their memory impairment. Depressed patients were more impaired as compared with euthymic patients on tests of verbal recall and fine motor skills. Psychosocial functioning was impaired across all three patient groups, but only in depressed and hypomanic patients did this correlate significantly with neuropsychological performance. Conclusions: The mood‐state‐related cognitive deficits in both bipolar depression and hypomania compromise psychosocial function when patients are unwell. In euthymic patients, subtle impairments in attention and memory suggest that an absence of symptoms does not necessarily equate to ‘recovery’. The possibility of persistent cognitive deficits in BD is an issue of profound clinical and research interest that warrants further investigation; however, future research needs to adopt more sophisticated neuropsychological probes that are able to better define state and trait deficits and determine their functional impact.