COPENHAGEN – The traditional treatment paradigm for patients with comorbid depression and insomnia has been to focus on the depression in expectation that the sleep problems will fade away with the depressive symptoms.
Dr. Kerstin Blom
Big mistake, Kerstin Blom, PhD, said during the annual congress of the European College of Neuropsychopharmacology.
That treatment strategy is insufficient, because untreated insomnia seldom improves. It hinders recovery from depression, increases the risk of new depressive episodes, and causes continued suffering because of poor sleep, asserted Dr. Blom, a clinical psychologist and researcher at the Internet Psychiatry Clinic at the Karolinska Institute in Stockholm.
She presented highlights of a series of three randomized, controlled trials for which she was first author. The take-home message: Insomnia with comorbid depression is not merely a symptom of depression; it requires specific treatment.
“Insomnia needs to be treated according to guidelines – that is, with cognitive-behavioral therapy – when it’s comorbid with depression,” she declared. “Insomnia therapy also treats comorbid depression, but it’s not so much the other way around. There are some effects on insomnia when you treat depression, but they’re not very large.”
The first study in her series included 43 adults with psychiatrist-diagnosed comorbid insomnia and major depression who were randomized to an 8-week course of psychologist-guided, Internet-delivered cognitive-behavioral therapy (ICBT) for one disorder or the other. At 6- and 12-month follow-up, patients who received ICBT for insomnia had significantly greater improvement in their insomnia as measured by the self-rated Insomnia Severity Index than did those who got ICBT for depression, while both forms of treatment were similarly effective in reducing depression severity as reflected in Montgomery-Åsberg Depression Rating Scale (MADRS) scores (Sleep. 2015 Feb 1;38[2]:267-77).
At 3-year follow-up, the beneficial impact of ICBT for insomnia remained strong, with recipients reporting less need for additional sleep treatment and less use of sleep medication than did the patients who got ICBT for depression. Both groups were left with mild depression, pointing to the need to develop a combined form of CBT that would simultaneously address both disorders in patients with comorbid depression and insomnia (Sleep. 2017 Aug 1;40[8]. doi. 10.1093/sleep/zsx108).
The Swedish investigators went on to create a 9-week course of psychologist-guided combination ICBT for both insomnia and depression. Then they randomized 126 dual-diagnosis patients to that treatment program or to therapist-guided ICBT for depression plus a placebo sleep intervention, which included education about sleep hygiene, stress management, and use of a sleep diary. At 6 months of follow-up, the dual-target ICBT group had a significantly greater reduction in Insomnia Severity Index scores than those who got ICBT for depression plus placebo. No between-group difference were found in the reduction in MADRS scores.
Dr. Blom observed. Follow-up out to 36 months is ongoing.
The third study included 148 nondepressed adults with insomnia who were randomized to the 8-week ICBT insomnia intervention or an active control treatment, which again included patient education, stress management, and a sleep diary. At 6 months, the active CBT-insomnia group had significantly lower Insomnia Severity Index scores than controls. However, at 12 and 36 months, the control group caught up, and there was no longer a between-group difference, with 74% of participants no longer meeting diagnostic criteria for insomnia at 36 months. The explanation for the catch-up? The control group used significantly more hypnotic sleep medications and more frequently sought additional insomnia treatments, including yoga and mindfulness, outside of the study setting during follow-up (Sleep. 2016 Jun 1;39[6]:1267-74).
It was Dr. Blom’s intent to also use this randomized, controlled trials to test the hypothesis that improving insomnia in nondepressed patients prevents future episodes of depression. She was thwarted in this attempt.
“After they got our low-intensity control version of a sleep intervention, they went out and got more treatment and that seems to have helped them, which is great,” Dr. Blom said. “But it sort of ruined our prediction study.”
However, in a post hoc analysis, study participants who were poor sleepers at 12 months had significantly more depressive symptoms at 36 months than did those with improved sleep at 12 months. The effect size was quite large, with a between-group 5.5-point difference in MADRS scores at 36 months in a study population that was nondepressed at baseline.
“So improved sleep may prevent depression long term,” Dr. Blom said. “The jury is still out on that one.”
She reported having no financial conflicts regarding her studies, which were supported by government research funding.