Daytime sleepiness common in bipolar disorder
MedWire News: Patients with bipolar disorder commonly experience excessive daytime sleepiness, which has a negative impact on functioning, researchers report.
The findings support excessive daytime sleepiness as a relevant clinical dimension in patients with the mood disorder that should be included in routine clinical assessments, say Flávio Kapczinski (Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil) and team.
As people with bipolar disorder, especially those with chronic illness, tend to have significant biological rhythm dysfunction, the team compared the prevalence of excessive daytime sleepiness in 81 euthymic patients with the mood disorder and 70 age-, gender-, and education level-matched mentally healthy individuals.
All of the participants were assessed for excessive daytime sleepiness using the Epworth Sleepiness Scale (ESS), with scores above 10 indicating its presence.
They were assessed for sleep quality and disturbances using the Pittsburgh Sleep Quality Index (PSQI). Also, functioning was evaluated using the Functioning Assessment Short Test (FAST), which includes items on autonomy, work, cognitive functioning, financial issues, and interpersonal relationships, with higher scores indicating poorer functioning.
The researchers found that the prevalence of excessive daytime sleepiness was significantly higher in bipolar disorder patients than controls, at 40% versus 18%, with the presence of sleep disturbance being a significant predictor of excessive daytime sleepiness in both groups.
Furthermore, the presence of excessive daytime sleepiness was significantly associated with poorer FAST scores in both groups.
Multiple regression analysis showed that sleep disturbance and excessive daytime sleepiness, but not use of sleep medication, were independent predictors for higher FAST scores.
Writing in Acta Neuropsychiatrica, Kapczinski and team conclude: "This study suggests that excessive daytime sleepiness is a relevant clinical dimension in patients with bipolar disorder. It is a frequent symptom that often overlaps with other sleep disturbances and once present it augments the patients' functional impairment."
They add: "Clinically, it is reasonable to ask about daytime sleepiness in the routine assessment of patients with bipolar disorder."
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By Mark Cowen