(269) Risk of Suicidal Behavior Associated with Benzodiazepines: A Nationwide Case-Crossover Study

Publication Number: 600

Background: Some recent studies have suggested that benzodiazepines might trigger suicidal behaviors but the association remains suspected of bias.

Objectives: This study aimed at estimating the risk of suicide attempt and suicide death associated with benzodiazepines using methods minimizing confounding factors.

Methods: Case-crossover (CCO) study, based on data from the French reimbursement healthcare system (SNDS). Participants: ≥16y, with a suicidal act identified between 2013 and 2016, and at least one benzodiazepine dispensing over the previous 120-day “observation period”. According to psychiatric history in the year before the observation period (yes/no), two populations were defined. Benzodiazepine dispensing was self-compared between a risk-period (days [-30, -1] before the act) and two reference periods (days [-120, -91] and [-90, -61]). Analyses were adjusted for time-varying confounders (psychotropic drugs). To strengthen bias control, we performed a second CCO using cyamemazine as a negative control with similar risk of indication bias, and a case-case-time-control design to address time-trend bias.

Results: Among the “non-psychiatric population”, 34,076 individuals attempted suicide (41.8% men; mean age, 44.8±18.0 years), and 4,354 deceased by suicide (77.7% men; 61.2±18.4 years). We found an increased dispensing of benzodiazepines in the 30 days before suicide attempt (adjusted OR 2.77; 95%CI: 2.69-2.86) and suicide (1.80; 1.65-1.97). Among the “psychiatric population”, 77,474 cases attempted suicide (33.1% men; 48.8±15.0 years) and 7,958 died from suicide (58.4% men; 56.7±16.0 years): benzodiazepine dispensing during the 30-day risk-period was significantly associated with both suicide attempt (1.74; 1.69-1.78) and suicide (1.45; 1.34-1.57). The risk persisted in the complementary analyses.

Conclusions: Using methods with increased bias control, this nationwide study supports an association between benzodiazepine and suicidal behaviors. Even if residual confounding cannot be ruled-out, these results strengthen the need for awareness and monitoring when prescribing benzodiazepines, and plea for the importance of screening for suicidal risk carefully before initiation.