The mediating role of insomnia in the relation between life events and depression and mania

Date of Award




Degree Name

Doctor of Philosophy (Ph.D.)



First Committee Member

Sheri Johnson - Committee Chair


The heterogeneous course of bipolar disorder suggests that multiple factors influence the expression of this chronic illness. Ehlers and colleagues (1988) as well as Wehr and colleagues (1987) propose that psychological, interpersonal, environmental, and pharmacological factors that appear to provoke the onset of depression and mania could act by means of their capacity to cause sleep disturbance. The current study is the first prospective study to examine the mediating role of insomnia in the relation between two types of life events (severe and sleep-disrupting) and depression and mania. Results indicate that individuals with severe life events report greater insomnia and insomnia predicts increased depression across six months. Furthermore, experiencing a severe life event predicts mania across a six-month time period. Sleep-disrupting life events do not appear to predict insomnia, depression, or mania. Conditions for establishing mediation were not met for either hypothesized life events model. The current study contributes to the previous literature that emphasizes the role of sleep, particularly insomnia, in bipolar disorder. In addition, it emphasizes the need to consider contextual influences that magnify the impact of life events and sleep disturbances on mania and depression. Insomnia exemplifies how biobehavioral dysregulation in bipolar disorder may increase vulnerability to additional stress. In future studies it will be important to evaluate both mediation and moderation models. A better understanding of sleep disturbances that contribute to changes in symptom severity not only will clarify the pathophysiology of depression and mania, but also will provide an opportunity for pharmacological, behavioral, or psychosocial interventions.


Psychology, Clinical

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