Clinical Context

Depression and insomnia are frequently comorbid and important illnesses among older adults. The authors of the current study provide a review of the relationship between depression and insomnia. The 1-year prevalence of depression among community-dwelling adults at least 60 years of age is more than 10%. Depression among older adults is associated with increased rates of cognitive decline and overall mortality, and older men have the highest rate of suicide of all age/sex groups.

Meanwhile, insomnia affects approximately half of adults at age 60 years or older, and the presence of insomnia doubles the risk for depression. Whereas sleep education therapy (SET) represents the bare minimum of care for insomnia, cognitive behavioral therapy (CBT) is recommended as a first-line treatment for insomnia. CBT directed at insomnia can improve sleep among adults with concomitant depression and insomnia, but it is less effective in improving depression in this setting.

The current study compares SET and CBT in a prospective study among older adults with insomnia. The main study outcome was incident depression over the course of 36 months of follow-up.

Study Synopsis and Perspective

Cognitive behavioral therapy (CBT) is linked to a significantly reduced risk for depression in patients with insomnia, new research shows.

Insomnia affects more than 50% of older adults and contributes to a 2-fold greater risk for major depression, the investigators note.

"We show that by treating insomnia with a simple behavioral approach called cognitive behavioral therapy for insomnia, or CBT-I, you can reduce the likelihood of developing depression by over 50%," lead author Michael R. Irwin, MD, Cousins Distinguished Professor of Psychiatry and Biobehavioral Sciences, Geffen School of Medicine, University of California, Los Angeles, told Medscape Medical News.

The study is unique in that the treatment "is not just reducing depression, it's preventing depression," Dr Irwin added.

The findings were published online November 24 in JAMA Psychiatry.^[1]

The study included 291 patients aged 60 years and older (mean age, 70 years; 58% women) with confirmed insomnia disorder and no major depression within the previous 12 months.

All were randomly assigned to receive either CBT-I or SET.

CBT-I is a first-line treatment for insomnia that includes 5 components that include cognitive therapy targeting dysfunctional thoughts about sleep, stimulus control, sleep restriction, sleep hygiene, and relaxation.

SET provides information on behavioral and environmental factors contributing to poor sleep. Although sleep education provides tips on improving sleep, CBT-I helps patients implement those changes and behaviors, Dr Irwin noted.

Both interventions were delivered by trained personnel in weekly 120-minute group sessions for 2 months, consistent with the format and duration of most CBT-I trials.

The primary outcome was time to incident or recurrent major depressive disorder as diagnosed by the Structured Clinical Interview of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, every 6 months during 36 months of follow-up. A monthly Patient Health Questionnaire 9 (PHQ-9) was used to screen for depressive symptoms.

Results showed that depression occurred in 12.2% of the CBT-I group vs 25.9% of the SET group. The hazard ratio (HR) for depression in the CBT-I group compared with the SET group was 0.51 (95% confidence interval [CI], 0.29-0.88; P=.02). The number needed to treat to prevent incident or recurrent depression was 7.3.

After adjusting for factors affecting depression risk such as sex, educational level, income, comorbidity, and history of depression, the HR for depression in the CBT-I group vs the SET group was 0.45 (95% CI, 0.23-0.86; P=.02).

Treatment with CBT-I yielded an annual 4.1% incidence of depression, which is similar to the population rate and half the rate in SET, which was 8.6%.

The secondary outcome was sustained remission of insomnia disorder. The investigators found that a greater proportion of the CBT-I group than the SET group achieved remission after treatment (50.7% vs 37.7%; adjusted β = 0.52; 95% CI, 0.10-0.93; P=.02).

"Remission is really key to the benefits that we're seeing," said Dr Irwin.

Inflammation may explain why insomnia raises the risk for depression, he noted. "We know sleep disturbance can lead to inflammation and we also know inflammation can produce depression."

It is also that possible insomnia leads to an impaired pleasure or reward system, which is linked to depression, he added.

The authors note that because insomnia is associated with suicidal ideation and dementia, CBT-I may also reduce risk for suicide or cognitive decline.

Although 8-week CBT-I treatments are readily available, "unfortunately, most clinicians will prescribe medications," said Dr Irwin. He noted that in older adults, drugs are linked to adverse events such as falls and cognitive problems.

These new results "really argue that psychology and psychiatry need to be fully integrated into what we call collaborative care models," Dr Irwin said.

There were no adverse events during treatment, and none of the serious events that occurred during follow-up were attributed to the trial.

Commenting on the findings for Medscape Medical News, Philip R. Muskin, MD, professor of psychiatry at Columbia University Irving Medical Center, New York City, said the study was "nicely written" and the authors put forward "a very convincing argument" for CBT-I to prevent depression.

"It's eye opening in that it's a robust study--it's carefully done, subjects were followed for a long period of time, and it's an accessible treatment," said Dr Muskin, who was not involved with the research.

The study also shows that "it's possible to intervene in something we know is a risk factor in elderly people," he added. "We think of older people as being less malleable to these kinds of things, but they're not. They clearly participated, and there wasn't a huge dropout rate."

Dr Muskin noted that less than half of the older participants were married or had a partner. He would have liked more information on this status because being widowed or divorced, as well as when this life change occurred, could affect vulnerability to depression.

The authors of an accompanying editorial called the study "seminal" and noted that insomnia treatment possibly preventing depressive disorders is a "major finding."^[2]

Proving that this preventive strategy is effective in older adults will be important because "insomnia and depression are highly prevalent in this population and the uptake of both preventive and treatment services is low," write Pim Cuijpers, PhD, from the Department of Clinical, Neuro, and Developmental Psychology, Amsterdam Public Health Research Institute, the Netherlands, and Charles F. Reynolds III, MD, from the Department of Psychiatry, University of Pittsburgh School of Medicine, Pennsylvania.

If the reduced rates of depression observed in the study could be generalized to the total population with insomnia, "the incidence of major depression could be reduced considerably," they write.

"Can we prevent depression through interventions aimed at procrastination in college students, interventions aimed at perfectionism in perinatal women, stress management training for employees, social skills training in adolescents?" they ask.

This approach to preventing depressive disorders "offers all kinds of new opportunities to develop and test indirect interventions" for problems that are significantly associated with the onset of depression, the editorialists write.

The study was funded by a grant from the National Institute on Aging to the University of California, which partially supported the authors' salaries. Dr Irwin, Dr Muskin, and Dr Cuijpers have reported no relevant financial relationships. Dr Reynolds reported being coinventor of the Pittsburgh Sleep Quality Index, for which he receives royalties.

JAMA Psychiatry. Published online November 24, 2021.

Clinical Implications

• The 1-year prevalence of depression among community-dwelling adults at least 60 years of age is more than 10%. Depression among older adults is associated with increased rates of cognitive decline and overall mortality, and older men have the highest rate of suicide of all age/sex groups. Meanwhile, insomnia affects approximately half of adults at age 60 years or older, and the presence of insomnia doubles the risk for depression.
• In the current study, CBT was superior to SET in the outcomes of incident or recurrent depression plus remission of insomnia in a cohort of older adults with baseline insomnia.
• Outline implications for the healthcare team: CBT can be an effective tool to prevent depression among older adults with insomnia. The healthcare team should consider CBT when caring for older adults with insomnia.

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