Do euthymic bipolar patients have normal cognitive functioning?

Purpose of review Research on the neurocognitive functions of bipolar patients has yielded inconsistent results over recent years. There is a growing need for clarification regarding the magnitude, clinical relevance and confounding variables of cognitive impairment in bipolar patients. Recent findings Current findings of studies investigating executive functions, psychomotor speed and memory functions suggest heterogeneous cognitive functioning in patients. A significant amount of variance can be attributed to treatment factors or interactions of those factors with the course of illness and individual characteristics. Furthermore, cognitive domains are presumably inter-related. The impact of bipolar illness on cognition can be influenced by age of onset, pharmaceutical treatment approaches, individual response, familial risk factors, and clinical features. Although brain activation patterns appear to be altered, these alternations do not necessarily correlate with impairment in cognitive performance. Without carefully controlling for confounding variables, the actual effect of bipolar disorder on cognitive performance scores cannot be evaluated. Summary Cognitive deficits of clinical relevance are documented for a substantial proportion, but not the majority, of bipolar patients. Yet, available data are inconclusive with respect to the origin of these deficits. Future studies on cognitive deficits in bipolar patients need to deliver detailed descriptions of drug treatment and clinical features.