Cognitive dysfunctions in bipolar disorder: Evidence of neuropsychologicaldisturbances

Although cognitive dysfunctions in psychosis have classically been associat ed with schizophrenia, there is clinical evidence that some bipolar patient s show cognitive disturbances either during acute phases or in remission pe riods. The authors critically review the data on cognitive impairment in bi polar disorder. The main computerized databases (Medline, Psychological Abs tracts, Current Contents) have been consulted crossing the terms 'cognitive deficits', 'neuropsychology', 'intellectual impairment', 'mania', 'depress ion' and 'bipolar disorder'. Changes in the fluency of thought and speech, learning and memory impairment, and disturbances in associational patterns and attentional processes are as fundamental to depression and mania as are changes in mood and behavior. Moreover, a significant number of bipolar pa tients show persistent cognitive deficits during remission from affective s ymptoms. However, there are several methodological pitfalls in most studies such as unclear remission criteria, diagnostic heterogeneity, small sample sizes, absence of longitudinal assessment, practice effect and poor contro l of the influence of pharmacological treatment. Most studies point at the presence of diffuse cognitive dysfunction during the acute phases of bipola r illness. Most of these deficits seem to remit during periods of euthymia, but some of them may persist in approximately one third of bipolar patient s. Methodological limitations warrant further research in order to clear up the relationship between neuropsychological functioning and clinical, demo graphic and treatment variables in bipolar disorder. Copyright(C)2000 S. Ka rger AG, Basel.