Exposure to psychotropic medications prior to overdose: a case-control study.

Rationale: Little is known about psychotropic medication prescriptions prior to drug overdose.

Objectives: We aimed to examine the possible associations between the risk of overdose and exposures to various psychotropic medications.

Methods: We conducted a matched case-control study of 3 groups of patients aged 12-74 years, using a large-scale health insurance claims database in Japan (population 1.2 million). A total of 351 cases with drug poisoning were compared with two control groups without overdose: 1755 patients with any treatment (general controls) and those with depression (high-risk controls). Current, past, and nonusers were patients most recently exposed to psychotropic medications ≤ 90 days, 91-180 days, and ≥ 180 days before the index date.

Results: Current sedative-hypnotic use was associated with an increased odds of overdose relative to general control nonusers (odds ratio [OR], 21.5; 95 % confidence interval [CI], 9.7-47.8) and high-risk control nonusers (OR, 2.6; 95 % CI, 1.9-3.5). In the comparison of cases and high-risk controls, the ORs for overdose were higher among excessive dosage users than among usual dosage users (OR, 4.3; 95 % CI, 3.0-6.1), among barbiturate users than among benzodiazepine/Z-drug only users (OR, 4.5; 95 % CI, 2.3-8.7), and among multiple provider episodes than among single provider episodes (OR, 4.4; 95 % CI, 1.7-11.0). Psychiatrists prescribed more than 77 % of potentially questionable prescriptions.

Conclusions: These results highlight the need for psychiatrists to monitor prescribed medications and balance the benefits and risks of pharmacological treatments.