Insomnia may be more than a problem of poor sleep. A systematic review and meta-analysis of 19 randomized controlled trials found that cognitive behavioral therapy for insomnia (CBT-I) was associated with lower suicidal-ideation severity after the intervention than control conditions.
The review included 4,974 randomized adults, 66% of whom were women. Its findings suggest that improving insomnia through CBT-I may coincide with a reduction in the severity of suicidal thoughts. However, the evidence does not establish CBT-I as a stand-alone suicide-prevention strategy, and the people at highest immediate risk were generally not represented in the trials.
What the review found
Compared with control conditions, CBT-I was associated with a 23% reduction in suicidal-ideation severity after treatment. The reported ratio of means was 0.77, with a 95% confidence interval of 0.66 to 0.90, across 16 studies.
The review also reported a 95% prediction interval of 0.65 to 0.91. This indicates that the estimated direction of the effect remained similar across the settings represented in the analysis.
The researchers reported no evidence of publication bias based on a contour-enhanced funnel plot and a non-significant regression test for funnel-plot asymmetry. Sensitivity analyses produced similar results after excluding studies with a high overall risk of bias, more than 20% dropout, waitlist control groups or a single-question measure of suicidal ideation.
The overall certainty of evidence for suicidal-ideation severity was judged to be high. However, 72% of trials had some concerns about risk of bias, 17% were judged to be at high risk and 11% were judged to be at low risk.
What CBT-I involves
CBT-I is described in the review as the recommended first-line treatment for chronic insomnia among adults. It combines sleep-hygiene education, cognitive restructuring, sleep restriction and stimulus control.
Insomnia can involve difficulty falling asleep, difficulty staying asleep, early-morning awakening and daytime impairment. The condition affects approximately one in 10 people in the general population and is described in the source as an independent, modifiable risk factor for suicidal ideation and behaviors.
The review found significant reductions in Insomnia Severity Index scores in the CBT-I groups compared with control groups. The reported mean difference was −4.09, with an interval of −5.09 to −3.10. The supplied report does not include the associated P value or later results for this analysis.
Why the findings need careful interpretation
The trials varied in how CBT-I was delivered. The number of studies using therapist-delivered CBT-I and self-guided digital CBT-I was balanced, and subgroup analyses did not find that effects were moderated by delivery format, age group, population or whether participants had been selected for recent or current suicidal ideation.
Still, only three trials selectively enrolled people with current or recent suicidal ideation, and one enrolled outpatients with present suicidal behaviors. People with a recent suicide attempt or at high suicide risk were generally excluded. As a result, the findings may not directly describe those facing the most acute risk.
Eleven trials were conducted in the United States. In trials reporting race or ethnicity, participants were predominantly White, and 11 studies were conducted in patient populations. Three included trials were unpublished, including one that ended because of recruitment failure. No trial was industry-funded.
The wider context
Suicide accounted for an estimated 746,000 deaths worldwide in 2021 and remains a major public health issue. Projections suggest a modest global decline in suicide deaths by 2050, but the source says that this would not be enough to meet the 2030 Sustainable Development Goals target of a one-third reduction.
Suicidal ideation refers to thoughts of suicide, with or without suicidal intent, and is described as a major risk factor for suicide attempts and deaths. The source estimates that about 30% of people who experience suicidal thoughts, plans or attempts in a given year seek or engage with mental health services. It also cites evidence that 50% to 60% do not disclose suicidal thoughts or behaviors to others.
These figures help explain the interest in treatments that address an established, modifiable condition such as insomnia. The review supports further consideration of CBT-I in research and clinical care, but its results should be understood as evidence of an association observed in trials—not proof that treating insomnia alone prevents suicide deaths or behaviors.
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