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

Little is known about psychotropic medication prescriptions prior to drug overdose. We aimed to examine the possible associations between the risk of overdose and exposures to various psychotropic medications. 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. 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. These results highlight the need for psychiatrists to monitor prescribed medications and balance the benefits and risks of pharmacological treatments.