BOSTON—Objective sleep duration moderates the probability of remission among patients with comorbid depression and insomnia, according to research presented at the 31st Annual Meeting of the Associated Professional Sleep Societies. Sleep durations of greater than five to six hours increase the likelihood that these patients will achieve insomnia remission with cognitive behavioral therapy for insomnia (CBT-I), but do not affect the likelihood of depression remission. Sleep durations of seven or more hours optimize the likelihood of insomnia remission and depression remission in response to CBT-I.
In a 2015 consensus statement, the Sleep Research Society recommended seven or more hours of sleep per night for adults younger than 60. Studies indicate that sleep durations of less than five hours and less than six hours are associated with increased morbidity and poor treatment response among patients with insomnia. “We wanted to know what [sleep-duration] cutoffs … might be better predictors of eventual insomnia and depression remission through treatment,” said Jack Edinger, PhD, Professor of Medicine at National Jewish Health in Denver.
An Analysis of the TRIAD Study
Dr. Edinger and colleagues conducted a secondary analysis of the TRIAD study, which examined whether combined treatment of depression and insomnia improves depression and sleep outcomes in participants with both disorders. Eligible participants met Diagnostic and Statistical Manual of Mental Disorders (4th ed.) criteria for major depression and primary insomnia, had a Hamilton Rating Scale for Depression (HAMD-17) score of 16 or greater, and had an Insomnia Severity Index (ISI) score of 11 or greater. People who had had psychotherapy in the previous four months, or had failed or could not tolerate previous adequate trials of the study medications, were excluded. Participants completed one night of baseline polysomnography before entering the treatment phase of the study.
The study population included 104 participants (75 women) with a mean age of 47. Mean baseline HAMD-17 score was 22, and mean baseline ISI score was 20.6. All participants received antidepressant medication (ie, citalopram, sertraline, or venlafaxine). Patients were randomized to CBT-I or sham (ie, a pseudodesensitization condition with sleep education). The investigators assessed participants biweekly with the HAMD-17 and the ISI. The treatment period lasted for 16 weeks.
CBT-I Provided Benefits
Participants with five or more hours of sleep were more likely to respond to CBT-I than participants with fewer than five hours of sleep. Among participants with sleep duration of five or more hours, insomnia remission was more likely with CBT-I than with the control condition. The five-hour cutoff had no association with depression remission.
Among participants with six or more hours of sleep, those who received CBT-I were more likely to achieve insomnia remission than controls. The six-hour cutoff did not affect the likelihood of depression remission, however.
Among participants with seven or more hours of sleep, those randomized to CBT-I were more likely to achieve insomnia remission and depression remission than controls.
“More research is needed to determine how best to achieve depression remission in those patients with less than seven hours of objective sleep duration prior to starting treatment,” Dr. Edinger concluded.
Bathgate CJ, Edinger JD, Krystal AD. Insomnia patients with objective short sleep duration have a blunted response to cognitive behavioral therapy for insomnia. Sleep. 2017;40(1).
Vgontzas AN, Liao D, Bixler EO, et al. Insomnia with objective short sleep duration is associated with a high risk for hypertension. Sleep. 2009;32(4):491-497.
Watson NF, Badr MS, Belenky G, et al. Recommended amount of sleep for a healthy adult: A joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep. 2015;38(6):843-844.