Megan Brooks

June 27, 2017

BOSTON — Patients with comorbid depression and insomnia who sleep at least 7 hours nightly are more likely to benefit from cognitive-behavioral therapy for insomnia (CBTI) and achieve depression remission, preliminary results from the Treatment of Insomnia and Depression (TRIAD) Study show.

Sleeping 7 hours or more nightly before starting treatment increased the chances of achieving both depression and insomnia remission, explained lead author and co-principal investigator, Jack D. Edinger, PhD, professor in the Section of Sleep Medicine at National Jewish Health in Denver, Colorado.

"More research is needed to determine how best to achieve depression remission in those patients with less than 7 hours of objective sleep prior to starting treatment," Dr Edinger told attendees at SLEEP 2017: 31st Annual Meeting of the Associated Professional Sleep Societies.

Sleep a Player in Recovery

Study participants included 104 adults (75 women; mean age, 47.8 years) meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria for major depressive disorder and primary insomnia. At baseline, mean Hamilton Rating Scale for Depression (HAMD-17) score was 22.5 and mean Insomnia Severity Index (ISI) was 20.6.  All participants completed one night of polysomnography at baseline.

Participants received 16 weeks of antidepressant medication and were randomly assigned to CBTI or sham insomnia therapy. The HAMD-17 and ISI were administered biweekly during treatment to determine depression and insomnia remission (scores < 8 on last observation).

Patients in the CBTI group who got at least 7 hours of sleep per night had a 62.5% depression remission rate at the end of the study. Remission rates for patients sleeping 5 or 6 hours a night were much lower, ranging from 18.2% to 42.1%, Dr Edinger reported.

This study shows that objective sleep duration moderates the probability of remission in patients with comorbid depression and insomnia, he noted. Sleep durations greater than 5 and greater than 6 hours increase the chances for insomnia remission with CBTI, but not depression remission. However, durations of greater than 7 hours optimize chances of both insomnia and depression remission in response to CBTI.

"Our findings highlight the importance of adequate objective sleep in the recovery from depression and insomnia. The data suggest that a short sleep duration may be a risk factor for refractory depression," study investigator Rachel Manber, PhD, from Stanford University Medical Center in Palo Alto, California, said in a conference news release.

Commenting on the study for Medscape Medical News, Shalini Paruthi, MD, spokesperson for the American Academy of Sleep Medicine (AASM), said, "It's important to remember that sleep comes from our brain and so does our mood and emotional regulation and irritability. So if one part of it isn't quite doing what it's supposed to be doing, it certainly can throw the other part off too."

"There is a bidirectional association between insomnia and depression, but causality is really hard to prove," Dr Paruthi noted. "There is also a link between sleep apnea and depression, with some studies showing that up to 20% of patients who are diagnosed with obstructive sleep apnea have depression. And if you take a cohort of depressed patients, up to 20% of them will have sleep apnea," she said. 

"Getting at least 7 hours of sleep, preferably more, and on a regular basis is important," Dr Paruthi added.

The study was supported by the National Institutes of Health. Dr Edinger and Dr Paruthi have disclosed no relevant financial relationships.

SLEEP 2017: 31st Annual Meeting of the Associated Professional Sleep Societies. Abstract 0335. Presented June 5, 2017.

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