Longitudinal relationship between clinical course and neurocognitive impairments in bipolar disorder.

Background: The aim of this study was to estimate the relationship between clinical course and trajectory of neurocognitive functioning during a follow-up period in a sample of euthymic bipolar patients.

Methods: Fifty-one patients with BD performed two-neurocognitive assessment separated by a period of at least 48 months. The clinical course during the follow-up period was documented by: three measures 1) number of affective episodes, 2) time spent ill, and 3) mood instability.

Results: Patients were followed-up for a mean period of 73.21 months. Neurocognitive performance tended to be stable throughout the follow-up. Performance in verbal memory and executive functions at the end of study were related with the number of hypo/manic episodes and time spent with hypo/manic symptoms during the follow-up. None of the clinical measures considered were related to changes in neurocognitive performance over the follow-up period.

Limitations: The relatively small sample size limits the value of subgroup analysis. The study design does not rule out some risk of selection bias.

Conclusions: Although there may be a positive relationship between number of episodes and neurocognitive deficits in patients with bipolar disorder, successive episodes do not seem to modify the trajectory of neurocognitive functioning over time. Theoretical implications of these findings are discussed.