The Prevalence of Insomnia Disorder in Inpatient Psychiatric Care

Sleep and mental health are intricately linked. Insomnia – defined as a dissatisfaction with sleep quantity or quality – is highly prevalent among patients with psychiatric disorders, exerting a negative impact on treatment outcome. However, the prevalence of insomnia on a symptom and diagnosis level (insomnia disorder) has not systematically been assessed in inpatient psychiatric care. The aim of this study was to systematically investigate the prevalence of insomnia symptoms and insomnia disorder according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria in inpatient psychiatric care. Comprehensive diagnostic interviews were conducted by trained clinicians in four German and two Swiss psychiatric hospitals. A total of 427 inpatients with psychiatric disorders across diagnostic groups were included (225 female, 200 male, 2 non-binary, mean age 40.8 ± 15.1 years, mean duration of psychiatric illness 8.6 ± 10.6 years). The prevalence of comorbid insomnia disorder, according to DSM-5 criteria, was 30.4