Sleep abnormalities in adolescents with major depressive disorder (MDD) are not associated with poorer long-term outcomes in young adulthood, according to naturalistic follow-up study results published in European Child & Adolescent Psychiatry. Rather, sleep-wake rhythm disturbances at baseline were associated with improved outcomes at 8 years.
Sleeping problems are common among adolescents with MDD and are associated with greater depression severity, more frequent suicidal thoughts, and worse psychosocial functioning. Anna S. Urrila, MD, of the department of public health solutions, mental health unit, National Institute for Health and Welfare in Helsinki, Finland, and colleagues sought to explore whether sleep symptoms in adolescents with MDD were associated with long-term outcomes.
Adolescent outpatients diagnosed with MDD were followed for 8 years over the course of treatment as usual. Of the original sample, 112 adolescents (mean age at 8-year follow-up, 24.6±1.91 years; 16.1% boys) completed the 8-year assessment, with baseline occurring between 1998 and 2001. The investigators used structured clinical interviews to assess sleep symptoms and psychosocial functioning and questionnaires to assess symptoms of depression and anxiety.
At the 8-year assessment, 18.8% of patients had clinically significant sleep symptoms and 20.5% had sub-threshold sleep symptoms. Patients with significant sleep disturbances had more severe depressive symptoms, worse current and past year psychosocial functioning, and greater anxiety severity (P <.001). However, the investigators found no association between sleep complaint severity and time spent ill during the follow-up period.
Surprisingly, adolescents with moderate sleep complaints and adolescents with multiple sleep disturbances at baseline demonstrated better outcomes as young adults. In adjusted models, adolescents with multiple sleep complaints at baseline had improved depressive and anxiety symptoms (both P =.03) at 8 years compared with those who had no or minor sleep disturbances. Similarly, compared with the reference group, adolescents with moderate sleep disturbances had less depressive symptoms (P =.007), lower anxiety (P =.04), and better global functioning (P =.005) at 8 years.
The investigators performed additional exploratory analyses of the types of sleep complaints — insomnia, hypersomnia, or sleep-wake rhythm disturbance. They found that patients with sleep-wake rhythm disturbances had better outcomes, with less depression (P =.008), fewer symptoms of anxiety (P =.016), and better psychosocial functioning (P =.002) at 8 years than those without such disturbances. These results were repeated in all adjusted regression analysis models. In contrast, those with insomnia or hypersomnia at baseline did not differ significantly in terms of outcome from patients with MDD and no sleep symptoms.
Study limitations included the lack of objective measures of sleep, including sleep-specific questionnaires, sleep logs, and detailed information on sleep symptoms at the 8-year follow-up, as well as the overrepresentation of girls in the study population.
“Since manipulations of the sleep-wake rhythm can be used as treatments for affective disorders, we can speculate that the deviations of the sleep-wake rhythm at baseline could have represented actually an (successful) attempt of the depressed adolescents to cope with their affective symptoms,” the investigators noted.
Urrila AS, Kiviruusu O, Haravuori H, et al. Sleep symptoms and long-term outcome in adolescents with major depressive disorder: a naturalistic follow-up study [published online November 6, 2019]. Eur Child Adolesc Psychiatry. doi:org/10/1007/s00787-019-01436z