Background: Data from the literature suggests the presence of cognitive impairments which persist in the euthymic phase of bipolar disorder (BD) and have significant consequences in regards to psychosocial functioning.
The aims of our study were: 1) to ascertain the cognitive function (CF), social disability (SD) and basic life skills (BLS) of euthymic patients diagnosed with BD, 2) their relationship and 3) to compare CF, SD and BLS in euthymic patients diagnosed with BD to euthymic patients with recurrent major depressive disorder (rMDD).
Subjects and methods: Ninety eight euthymic patients diagnosed either with BD (N=48, mean age 48.79 years, SD = 8.587) or rMDD (N=50, mean age 50.02 years, SD = 9.826) underwent testing using the Brief Assessment of Cognition in Affective Disorders (BAC-A) test, the Sheehan Disability Scale (SDS) and the UCSD performance-based skills assessment (UPSA-brief).
Results: Euthymic patients with BD demonstrated significantly lower scores as compared to normal population values in verbal, learning and working memory, verbal fluency, attention and processing speed, affective memory for negative and positive words (p<0.01 each) and motor speed (p<0.05), but not for reasoning/problem solving (p=0.05). Furthermore, their mean total SDS score of 17.60 (SD = 6.450, Sk = -0.833) and its subscale scores were higher, while their UPSA-B total scores were lower (M = 76.01, SD = 17.148, Sk = -0.412). There was a correlation between CF, SD and BLS scores (p<0.01), as well as between BLS and SD scores (p<0.05). The analysis of variance did not however show significant differences between subgroups of patients.
Conclusion: Patients with euthymic BD had lower cognitive function, greater social disability and lower basic life skills. There were similar decreases in cognitive and psychosocial function between patients in the euthymic phase of either BD or MDD.