Jennifer Kanady

© 2015 American Psychological Association.Objective: To determine if a treatment for interepisode bipolar disorder I patients with insomnia improves mood state, sleep, and functioning. Method: Alongside psychiatric care, interepisode bipolar disorder I participants with insomnia were randomly allocated to a bipolar disorder-specific modification of cognitive behavior therapy for insomnia or psychoeducation as a comparison condition. Outcomes were assessed at baseline, the end of 8 sessions of treatment, and 6 months later. This pilot was conducted to determine initial feasibility and generate effect size estimates. Results: During the 6-month follow-up, the CBTI-BP group had fewer days in a bipolar episode relative to the PE group. The CBTI-BP group also experienced a significantly lower hypomania/mania relapse rate and a marginally lower overall mood episode relapse rate compared with the PE group. Relative to PE, CBTI-BP reduced insomnia severity and led to higher rates of insomnia remission at posttreatment and marginally higher rates at 6 months. Both CBTI-BP and PE showed statistically significant improvement on selected sleep and functional impairment measures. The effects of treatment were well sustained through follow-up for most outcomes, although some decline on secondary sleep benefits was observed. Conclusions: CBTI-BP was associated with reduced risk of mood episode relapse and improved sleep and functioning on certain outcomes in bipolar disorder. Hence, sleep disturbance appears to be an important pathway contributing to bipolar disorder. The need to develop bipolar disorder-specific sleep diary scoring standards is highlighted.

Sleep disturbance and cognitive dysfunction are two key domains of impairment during the inter-episode phase of bipolar disorder. Despite considerable evidence demonstrating the importance of sleep for cognition in healthy and sleep-disordered samples, this link has been minimally examined in bipolar disorder. Thus, the present study tested the association between insomnia-related sleep disruptions and cognitive functioning during inter-episode bipolar disorder. Forty-seven participants with bipolar disorder and a comorbid insomnia diagnosis and 19 participants with bipolar disorder without sleep disturbance in the last six months participated in the study. Two domains of cognitive functioning were assessed: working memory and verbal learning. Insomnia-related sleep disruptions were assessed both categorically and dimensionally. Hierarchical linear regressions, adjusting for participant age, demonstrated that insomnia diagnosis did not have an independent or interactive effect on cognition. However, regardless of insomnia diagnosis, greater total wake time predicted poorer working memory performance and greater sleep duration variability predicted poorer working memory and verbal learning performance. Further, following sleep treatment, a reduction in total wake time predicted improved working memory performance and a reduction in sleep duration variability predicted improved verbal learning performance. These findings raise the possibility that sleep disturbance may be one mechanism underlying cognitive dysfunction in bipolar disorder and highlight the importance of treating sleep disturbance in bipolar disorder.