Concomitant use of alcohol and benzodiazepine hypnotics in psychiatric outpatients: A cross-sectional survey

Concomitant use of benzodiazepines and alcohol appears prevalent in a clinical setting. The objectives of this study were as follows: (1) to investigate the prevalence of concomitant use of benzodiazepine hypnotics and alcohol in psychiatric outpatients, (2) to examine the clinical characteristics and factors associated with the concomitant use, and (3) to investigate the awareness of the psychiatrists-in-charge about the concomitant use. Outpatients with schizophrenia, depression, and insomnia who were receiving benzodiazepine hypnotics were asked to fill in a sleeping diary for seven consecutive days in which use of hypnotics and alcohol was also recorded. Clinical characteristics were assessed, and logistic analysis was performed to examine factors associated with the concomitant use. In addition, psychiatrists-in-charge were asked as to whether they thought their patients were concomitantly using them. The prevalence rate of the concomitant use was 39.8% (37/93). The CAGE score showed significant positive association with the concomitant use (odds ratio = 2.40, 95% confidence interval = 1.39-4.16, P = 0.002). Only in 32.4% of the concomitant users were suspected by their psychiatrists. The results suggest that concomitantly used benzodiazepine hypnotics and alcohol appears prevalent, and has been frequently overlooked by treating psychiatrists. The CAGE questionnaire may be helpful to screen such potentially hazardous users.