Introduction: Hypnotics have been linked to a variety of adverse effects including addiction. Long term use of these drugs has been associated with an increased risk of suicide.
Aim: We aimed to assess if individuals in treatment with benzodiazepine (BZD) and non-benzodiazepine (n-BZD) had higher rates of suicide when compared to individuals not in treatment with these drugs.
Methods: We applied a cohort design to national longitudinal data on all individuals aged 10 or above who lived in Denmark between 1995 and 2021. Treatment with either BZD or n-BZD was identified via the Danish National Prescription Registry and suicide deaths were identified in the Cause of death Register.
Results: A total of 3,647,837 males and 3,663,793 females were observed over 60,402,486 and 62,278,883 person-years, respectively. Among those, 58,247 males and 72,644 females were treated with BZD, of which 678 males and 553 females died by suicide while being in on-going treatment with BZD, resulting in respective adjusted IRRs of 2.1 (95% CI, 1.9-2.4) and 2.6 (95% CI, 2.3-3.0), when compared to those not in treatment. Among 91,842 males and 104,258 females who were in treatment with n-BZD, a total of 1,774 males and 1,212 females died by suicide whilst in treatment and the adjusted IRRs were 3.4 (95% CI, 3.1-3.7) and 3.6 (95% CI, 3.4-3.9), respectively. Increased rates of suicide attempt were observed for both males and females in treatment with BZDs and n-BZDs.
Conclusions: Individuals in treatment had higher suicide rates than those not in treatment, this persisted when also adjusting for a large variety of covariates. Thus, monitoring mental state in those receiving BZD/n-BZD is warranted.