Association Between Zolpidem and Suicide: A Nationwide Population-Based Case-Control Study

Objective: To evaluate the association between zolpidem and the risk of suicide. Patients and Methods: In this nationwide case-control study, the case group comprised 2199 people who committed suicide or were hospitalized due to suicide attempt between January 1, 2002, and December 31, 2011. To create a control group, we randomly selected 10 people matched to each case according to age, sex, urbanization, and occupation. We measured the risk of suicide/suicide attempt in association with zolpidem exposure by using adjusted odds ratios (ORs) and assessed the dose-response effect of zolpidem. Results: After adjustment for potential confounders such as the comorbidities of schizophrenia, major depression, bipolar disorder, anxiety, insomnia, substance use, and other mental disorders, the Charlson comorbidity index, and use of benzodiazepine or antidepressants, zolpidem exposure was found to be significantly associated with the risk of suicide/suicide attempt with an OR of 2.08 (95% CIs, 1.83-2.36). The risk increased with the level of zolpidem use. The ORs (95% CIs) for cumulative defined daily doses of less than 90, 90 to 179, and 180 mg or more were 1.90 (1.65-2.18), 2.07 (1.59-2.67), and 2.81 (2.33-3.38), respectively (for trend, P<.001). Subgroup analyses showed that the exposure to zolpidem consistently increased the OR in different age groups, sex, urbanization level, occupation, mental disorders, and Charlson comorbidity index levels and in groups of people with or without the presence of insomnia. Conclusion: This study demonstrated a significant association between using zolpidem and suicide or suicide attempt in people with or without comorbid psychiatric illnesses (all P<.05). (C) 2016 Mayo Foundation for Medical Education and Research