The Functions of Non-Suicidal Self-Injury

Non-Suicidal Self-Injury (NSSI) is a fundamentally functional behaviour, motivated implicitly or explicitly, by an attempt to meet important needs for the individual. In this chapter we review the extant research into the functions of NSSI. We describe the findings of research into the common functions of NSSI, their prevalence, structure, and correlates. Notably, whilst the regulation of internal affective states is the most commonly endorsed function of NSSI, many other functions, both intrapersonal and interpersonal, also exist which can occur instead of, or in addition to, affect-regulation. A key observation is that the functions NSSI serves, whilst often considered in terms of general categories, are unique to the individual and emerge from the broader context of their life and individual needs. We outline clinical and research implications arising from the literature so far. These include the importance of considering the individual functions of NSSI as part of a broader psychosocial assessment. This includes discussion of how what we know about the functions of NSSI may help to guide intervention and prevention efforts. We identify other important implications of the essentially functional nature of NSSI for clinical practice. These include the potential challenges for building an effective therapeutic relationship where a therapist’s goals (e.g. to stop an individual self-injuring) differ from the goals of the client. We note that future research investigating the longitudinal temporal characteristics of self-injury and its underlying functions, and how these functions operate within the context of individuals’ day to day lives, would be of value.