Heterogeneity in cognitive functioning among patients with bipolar disorder

Background: Nowadays it is not clear if in bipolar disorders (BD) cognitive impairments are heterogeneous and if so which are the variables that determine it. Methods: Fifty patients with BD and thirty healthy controls were clinically evaluated including measures of obstetric complications history. All subjects completed an extensive neuropsychological battery selected to asses premorbid IQ and different cognitive domains. Results: Compared with standardized norms, 38% of patients had none cognitive domain affected, while 40% had 1 to 2, and 22% had 3 to 5. Patients with cognitive functioning within normal limits had higher psychosocial functioning and premorbid IQ, and lower history of obstetric complications. Limitations: The small sample size could limit the generalizability of the results; since these data should be taken as preliminaries. Conclusions: The extension and severity of cognitive impairments may be heterogeneous in patients with BD, and it might contribute to explain the variability in functional outcome. Bipolar patients with low premorbid IQ and history of obstetric complications may represent a subgroup with lower cognitive performance and psychosocial functioning. (C) 2007 Elsevier B.V. All rights reserved.