Self-injury in Japanese junior and senior high-school students: Prevalence and association with substance use.

The present study examined the prevalence of self-injury and its association with substance abuse in 2974 junior and senior high-school students, by self-reporting questionnaires. Consequently, 9.9% of students (boys, 7.5%; girls, 12.1%) reported an experience of self-injury at least once. Significant differences were found in substance use-related problems including alcohol abuse, smoking, and illicit drug use (P < 0.001) between students with and without an experience of self-injury. The results also suggest that self-injuring students may more easily gain access to illicit drugs even if they had not yet experienced the use of illicit drugs. Self-injury in adolescence may be associated with substance use and is considered to be a risk factor predicting future illicit drug use.