The prevalence of insomnia in depressed adults: a systematic review

Insomnia increases the risk of, and relapses in, depressive disorders. The treatment of insomnia in people with depression is associated with improvements in sleep, depressive symptoms, and overall patient outcomes. However, clinical services remain largely focused on depressive symptoms and access to gold standard evidence-based insomnia treatments remains limited. Accurate prevalence rate estimates of insomnia in depression are important for optimising effective clinical services. We aimed, therefore, to estimate in a systematic review of all relevant studies, the prevalence rate of insomnia in depressed adults.

We searched databases including Ovid and PubMed from inception to October 2024 for studies of currently depressed adults which reported the prevalence of insomnia symptoms. Two independent reviewers assessed articles and extracted data.

5021 unique references were identified, of which 82 full texts were reviewed after title and abstract screening. Fourteen studies, with a combined 10,337 participants, met the inclusion criteria. Eight studies were from the US, and one each from Belgium, China, the Netherlands, Republic of Korea, and Turkey, while one included participants from both Malaysia and Australia. The mean prevalence rate of insomnia symptoms in depressed adults was 78 % (95 % CI 70 % to 85 %), N = 10,337.

The high prevalence rate, consistent with previously reported estimates, suggests that insomnia is both common and under-treated in depressed adults. Given this, and that insomnia symptoms in adults with depression are infrequently treated directly despite evidenced-based, effective, acceptable treatments existing, clinical services should routinely offer targeted interventions to identify and manage co-incident insomnia symptoms.