Clinical Characteristics of Over-The-Counter Drug Misusers in Psychiatric Practice in Japan: Comparison by Type of Drug Misused for the First Time.

PURPOSE: This study aimed to understand the clinical characteristics of individuals who misuse over-the-counter (OTC) drugs in psychiatric clinical settings in Japan, and to reconsider approaches to current drug misuse prevention education and support strategies in Japan.

METHODS

Data were obtained from the 2024 Nationwide Survey on Drug-Related Disorders in Psychiatric Inpatient Facilities in Japan. Patients for whom OTC drugs were the primary substance of abuse were identified, and their demographic profiles, ICD-10 subcategories, and comorbid psychiatric disorders were examined. On the basis of the substance initially misused, participants were classified into three groups: illicit drugs, prescription drugs, and OTC drugs. Comparative analyses were conducted to assess clinical characteristics across these groups.

RESULTS

A total of 389 participants were included in the analysis: 36 in the illicit drug group, 47 in the prescription drug group, and 306 in the OTC drug group. Compared with the other groups, the OTC drug group exhibited a significantly higher proportion of female patients, adolescents, and individuals enrolled in junior or senior high school. Furthermore, this group demonstrated significantly lower rates of criminal history and engagement with support or treatment services, such as self-help groups, addiction-focused group therapy, and psychiatric hospitalization. In contrast, the prevalence of comorbid psychiatric disorders was significantly higher in the OTC drug group compared with the other two groups. Within the ICD-10 subcategories, "harmful use" was notably more frequent in the OTC drug group compared with the other groups.

CONCLUSION

The findings of this study indicate that OTC drug misuse has become a significant public health concern among adolescent females in Japan. The present findings underscore the necessity of reconsidering existing drug misuse prevention education and support frameworks, which have traditionally been oriented toward illicit substances.