Associations between general sleep quality and measures of functioning and cognition in subjects recently diagnosed with bipolar disorder

The present study aims to assess the association between sleep quality and the functional and cognitive impairment in subjects that recently converted to bipolar disorder (BD), subjects with past major depressive disorder (MDD) and subjects with recurrent MDD. This was a cross-sectional study corresponding to a second wave of a cohort study with a community sample. The first wave included 585 subjects diagnosed with MDD. Mood episodes were assessed through structured clinical interview. Functional and objective cognitive impairments were measured by the Functional Assessment Short Test (FAST) and Letter-number sequencing from Wechsler Adult Intelligence Scale III, respectively, and Cognitive Complaints in Bipolar Disorder Rating Assessment (COBRA) was used for subjective cognition measure. Sleep quality was assessed by Pittsburgh Sleep Quality Index (PSQI). In PSQI, FAST and COBRA, we found significantly worse scores in the BD and recurrent MDD groups when compared to past MDD group. Our findings also showed a significant association between functioning and subjective cognition with general sleep quality in all observed groups. We reinforce the need to follow-up for maintenance of functional and cognitive impairment, notably with BD patients, who may suffer in addition to damage caused by sleep alterations, also with neuroprogression in the long term.