Does Treating Insomnia Help Prevent Depression?

Insomnia and depression are intimately related. The majority of individuals with depression suffer from insomnia, and individuals with insomnia are more likely to develop depression than those without insomnia. For example, insomnia is associated with a twofold greater risk of developing depression in individuals over 60 years of age.

Insomnia is very common in the elderly. It is associated with the development of depression in those without a prior history of depression and with a reoccurrence of depression in those who have had prior depressive episodes.

Although many elderly individuals with depression respond partially to medications and/or psychotherapy, only about a third experience complete remission of symptoms. Preventing depression would likely be a more effective approach at alleviating suffering and disability than treating symptoms once they occur. In a paper published recently in JAMA Psychiatry, Michael Irwin and colleagues report the results of a study examining the effect of treating insomnia on subsequent development of major depression in individuals 60 years and older.

Cognitive behavioral therapy for insomnia (CBT-I) is an effective treatment for insomnia. It is recommended as the first-line treatment for insomnia disorder and is more effective than other widely used nonpharmacologic approaches, including sleep education therapy (SET). SET “targets day-to-day behavioral and environmental factors that contribute to poor sleep” and involves providing hygiene information about “sleep, sleep biology, characteristics of healthy sleep, stress biology, and impact on sleep.”

Irwin and colleagues enrolled a community sample of 291 individuals 60 years or older who had confirmed insomnia disorder. Persons with an episode of major depression in the previous 12 months were excluded from the study. Participants were randomly assigned to receive either CBT-I or SET in weekly two-hour group sessions for two months. CBT-I was administered by a trained psychologist; SET was delivered by a trained public health educator. Participants were monitored for the incidence of a major depressive episode over the subsequent 36 months using the Structured Clinical Interview of the DSM-5 (SCID-5).

The investigators found that the CBT-I-treated group had a 50% lower chance of developing depression than the SET-treated group. About 26% of those who received SET developed depression versus about 12% in the CBT-I group. More people in the CBT-I group experienced remission of their insomnia disorder: 51% versus about 38% in the SET group.

The research team also looked at the incidence of depression in those who experienced sustained remission of insomnia versus those who failed to achieve sustained remission. They found that only 5% of those who experienced insomnia remission in the CBT-I group developed a consequent episode of major depression versus 19% of those experiencing remission in the SET group. For those who did not achieve remission of insomnia, 15% in the CBT-I group developed a depressive episode versus 28% in the SET group. Thus, treatment with CBT-I was associated with preventing subsequent depression even in those whose insomnia did not fully remit.

As discussed in an accompanying commentary by Pim Cuijpers and Charles Reynolds, these results demonstrate the ability to prevent the development of depression in a high-risk group, ie, elderly individuals with insomnia. Would such a strategy work in younger individuals with insomnia? Would effective pharmacological treatments for insomnia have similar effects? Could parallel strategies be developed to treat other conditions that increase the risk of developing depression?

It is important to determine whether the results from the Irwin et al. study replicate in larger clinical trials. Forms of CBT-I that can be administered electronically (digital CBT-I episode) are available, and if also effective in preventing depressives, they could provide broader access to this potentially important intervention. We also note that insomnia is a common residual symptom of depression that puts individuals at risk for relapse. It would be important to determine whether CBT-I is an effective relapse prevention strategy.

Worldwide, depression is one of the most disabling of all illnesses. It is highly associated with suicide completed. In addition, mortality from other illnesses is increased when depression is also present.

Successful treatment of depression is important. Prevention of depression could change the lives of many individuals for the better.

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Eugene Rubin MD, PhD, and Charles Zorumski, MD, wrote this post.

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