Non-suicidal self-injury in United States adults: prevalence, sociodemographics, topography and functions.

BACKGROUND: Non-suicidal self-injury (NSSI) has received increased attention in the mental health literature and has been proposed as a diagnostic entity for DSM-5. However, data on NSSI in the United States adult population are lacking.

METHOD: The prevalence and nature of NSSI were examined in a random-digit dialing sample of 439 adults in the United States. Participants were recruited during July and August of 2008.

RESULTS: Lifetime prevalence of NSSI was 5.9%, including 2.7% who had self-injured five or more times. The 12-month prevalence was 0.9%. Methods of NSSI reported included cutting/carving, burning, biting, scraping/scratching skin, hitting, interfering with wound healing and skin picking. Half of self-injurers reported multiple methods. The average age of onset was 16 years (median 14 years). Instances of NSSI infrequently co-occurred with suicidal thoughts and with use of alcohol or drugs and rarely required medical treatment. Most injurers reported that NSSI functioned to alleviate negative emotions. Fewer reported that they self-injured to punish themselves, to communicate with others/get attention or to escape a situation or responsibility. NSSI was associated with younger age, being unmarried and a history of mental health treatment, but not with gender, ethnicity, educational history or household income.

CONCLUSIONS: Results are largely consistent with previous research in adolescent and young adult samples. Study limitations notwithstanding, this study provides the most definitive and detailed information to date regarding the prevalence and characteristics of NSSI in US adults. In the future, it will be important for large-scale epidemiological studies of psychopathology to include questions about NSSI.