Neuropsychological profile in bipolar disorder:: a preliminary study of monotherapy lithium-treated euthymic bipolar patients evaluated at a 2-year interval

Objective: To investigate the cognitive impairment of a sample of euthymic bipolar patients treated with lithium monotherapy at baseline in a 2-year longitudinal study. Method: Fifteen DSM-IV-TR bipolar out-patients and 15 healthy-matched controls were cognitively assessed twice over a 2-year follow-up. All patients underwent lithium monotherapy on the first evaluation, and they were euthymic in both evaluations. Cognitive assessment was performed by means of a neuropsychological test battery tapping into the main cognitive domains (executive function, attention, processing speed, verbal memory and visual memory). Results: Repeated measures multivariate analysis of variance showed that the bipolar disorder group was cognitively impaired in the executive domain, attention and processing speed, and such deficits were maintained over time. Conclusion: Our results showed that executive dysfunction is the main long-term neuropsychological deficit of bipolar disorder. Also, the persistence of these deficits did not seem to be influenced by any clinical or pharmacological variables.