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.