Sedative-hypnotics are associated with additional risk of suicide in older adults: a population-based case-control study.

Study objectives: To examine the pattern of sedative-hypnotic prescriptions associated with the risk of suicide behavior among older adults with and without insomnia.

Methods: The study included 8 319 suicide cases and age- and sex-matched controls from the population-wide National Health Insurance Research Database. Suicide methods and insomnia were defined using diagnostic codes. The sedative-hypnotic use pattern was categorized by half-life, prescription volume measured in Defined Daily Doses (DDDs), and its temporal relationship with suicide. Odds ratios were employed to assess the risk of insomnia and the prescription patterns of sedative-hypnotics on suicide. Additionally, we compared suicide methods between sedative-hypnotics users and nonusers.

Results: Insomnia was mildly associated with suicide behavior after adjusting for mental illnesses (adjusted RR = 1.82, OR = 1.86, 95% CI = 1.76-1.97), but the prescription of sedative-hypnotics was associated with 5-fold suicide risk (adjusted RR = 5.22, OR = 5.90, 95% CI = 5.11-6.82). Among patients with insomnia, a prescription volume of ≥ 31 DDDs per year, and a prescription within 90 days of the suicide index date were associated with increased suicide risk. Individuals prescribed sedative-hypnotics were more likely to suicide by methods involving sedative-hypnotic poisoning (21% vs. 0%).

Conclusions: Among older adults, sedative-hypnotic prescription is associated with increased suicide risk and suicide by self-poisoning using such medications. Non-pharmacological treatment for insomnia, such as cognitive behavioral therapy, is essential for suicide prevention.