Prevalence and correlates of alpha-delta sleep in major depressive disorders

Objective. Major depressive disorder is associated with sleep disturbances. An electroencephalographic pattern of alpha wave intrusion in delta wave sleep (alpha-delta sleep) is observed in some subjects with major depressive disorder. The treatment-resistant symptoms in major depressive disorder, nonrestorative sleep and fatigue, are associated with alpha-delta sleep. The objective of this study is to identify the prevalence and clinical correlates of alpha-delta sleep in major depressive disorder.Design. Retrospective studySetting. Sleep Disorders Center, Cleveland Clinic, Cleveland, OhioParticipants. Polysomnograms were conducted on 150 subjects 18 years of age or older (75 with and 75 without major depressive disorder) were reviewed.Measurements. The percent of delta waves with alpha intrusion was collected and analyzed.Results. Subjects with major depressive disorder compared to nondepressed subjects had a higher sleep efficiency (83.0±9.6; 78.1±8.2%), shorter rapid eye movement latency (85.0±44.5; 189.9±25.6 min), less slow wave sleep (8.3±3.0; 13.5±6.2%), and greater rapid eye movement (24.7±7.0; 19.2±8.2%), and all of these findings were statistically significant. Patients with major depressive disorder had higher alpha-delta sleep (23.4±14.2%; 2.3±6.7%, p<0.01). Patients with major depressive disorder were categorized into high and low alpha-delta sleep based on percentage of alpha-delta sleep present in slow wave sleep (alpha-delta sleep was present ≥15% or ≤15% of slow wave sleep, respectively). Patients with major depressive disorder with high alpha-delta sleep were at 3.15 greater odds (1.22-8.14; p=0.018) to have excessive daytime sleepiness.Conclusion. Patients with major depressive disorder have a higher prevalence of alpha-delta sleep. Alpha-delta sleep is associated with daytime sleepiness in patients with major depressive disorder. Study limitations include the retrospective nature of the project and the fact that the principle investigator, who scored and interpreted alpha intrusion, was not blind to group membership.