The functions of deliberate self-injury: a review of the evidence.

Deliberate self-injury is defined as the intentional, direct injuring of body tissue without suicidal intent. The present article reviews the empirical research on the functions of self-injury. This literature includes self-reports of reasons for self-injuring, descriptions of the phenomenology of self-injury, and laboratory studies examining the effects of self-injury proxies on affect and physiological arousal. Results from 18 studies provide converging evidence for an affect-regulation function. Research indicates that: (a) acute negative affect precedes self-injury, (b) decreased negative affect and relief are present after self-injury, (c) self-injury is most often performed with intent to alleviate negative affect, and (d) negative affect and arousal are reduced by the performance of self-injury proxies in laboratory settings. Studies also provide strong support for a self-punishment function, and modest evidence for anti-dissociation, interpersonal-influence, anti-suicide, sensation-seeking, and interpersonal boundaries functions. The conceptual and empirical relationships among the different functions remain unclear. Future research should address the measurement, co-variation, clinical correlates, and treatment implications of different functions.