Association between benzodiazepines and suicide risk: a matched case-control study

Background It is unclear whether benzodiazepines increase the risk of suicide. The aim of this study was to test the hypothesis that benzodiazepines are associated with an increased risk of suicide, by comparing psychopharmacological interventions between psychiatric patients who committed suicide and a group of matched controls. Methods The case group comprised 154 psychiatric patients (101 men, 53 women; age range: 13-96 years) who had committed suicide in orebro County, Sweden. Control psychiatric patients matched by age, sex, and main psychiatric diagnosis were selected for each case. Binary logistic regression was used to calculate odds ratios in unadjusted and adjusted models. Results Benzodiazepine prescriptions were more common among cases than controls (65/154 [42.2%] versus 43/154 [27.9%], p = 0.009, odds ratio: 1.89 [95% CI: 1.17-3.03]). This association remained significant in a model adjusted for previous suicide attempts and somatic hospitalizations (odds ratio: 1.83 [95% CI: 1.06-3.14]). No statistically significant differences were seen between the groups in the use of any other subtype of psychopharmaceutical agent. Conclusions These data indicate that benzodiazepine use may increase the risk of suicide. However, this study is limited by the potential for indication bias.