Cognitive function in adulthood and elderly euthymic bipolar patients: a comparison to test models of cognitive evolution

Abstract

Objective: Neurocognitive dysfunction is considered as the main predictor of overall outcome of BD. The issue of whether neurocognitive dysfunction in BD is progressive-or not-has become critical in the effort to define staging models for these disorders. Data about cognitive dysfunction evolution are scarce and contradictory. While some studies showed a progressive pattern others have found a stable form of evolution.

Methods: Twenty four patients with BD aged 60 years or older (E-BD), 24 patients with BD aged 40 years or younger (Y-BD) and 20 healthy controls matched by the E-BD group were evaluated with traditional clinical instruments and an extensive neuropsychological battery was completed. We used ANOVA and Chi-squared for comparisons. Raw score of neurocognitive tasks was transformed to standardized Z-score from the normative data of each test to avoid the effect of age. In order to decrease the risk of type I errors, one-way multivariate analysis of variance was conducted.

Results: Despite having an illness duration that was 4 times longer, E-BD did not differ in terms of key cognitive domains compared to Y-BD. These data do not support the hypothesis of a progression of cognitive dysfunction due to illness chronicity.

Keywords: Bipolar disorder; Cognition; Evolution; Progression; Staging.