Non-suicidal self-injury among adolescents: Diagnostic correlates and relation to suicide attempts Matthew K. Nock a, ⁎ , Thomas E. Joiner Jr. b , Kathryn H. Gordon b , Elizabeth Lloyd-Richardson c , Mitchell J. Prinstein d a Department of Psychology, Harvard University, 33 Kirkland Street, 1280, Cambridge, MA 02138, USA b Department of Psychology, Florida State University, Tallahassee, FL 32306, USA c Centers for Behavioral and Preventive Medicine, Brown Medical School, Providence, RI 02903, USA d Department of Psychology, University of North Carolina, Chapel Hill, NC 27599, USA Received 2 January 2006; received in revised form 9 March 2006; accepted 8 May 2006 Abstract Non-suicidal self-injury (NSSI) is a prevalent behavioral problem, yet many fundamental aspects of NSSI remain unknown. This case series study reports on the diagnostic correlates of adolescents with a recent history of NSSI and examines the relation between NSSI and suicide attempts. Data are from clinical interviews with 89 adolescents admitted to an adolescent psychiatric inpatient unit who engaged in NSSI in the previous 12 months. Results revealed that 87.6% of adolescents engaging in NSSI met criteria for a DSM-IV Axis I diagnosis (M = 3.0, S.D. = 2.2, range = 0 to 8 diagnoses), including externalizing (62.9%), internalizing (51.7%), and substance use (59.6%) disorders. Most adolescents assessed also met criteria for an Axis II personality disorder (67.3%). Overall, 70% of adolescents engaging in NSSI reported a lifetime suicide attempt and 55% reported multiple attempts. Characteristics of NSSI associated with making suicide attempts included a longer history of NSSI, use of a greater number of methods, and absence of physical pain during NSSI. These findings demonstrate the diagnostic heterogeneity of adolescents engaging in NSSI, highlight the significant overlap between NSSI and suicide attempts, and provide a point of departure for future research aimed at elucidating the relations between non-suicidal and suicidal self-injury. © 2006 Elsevier Ireland Ltd. All rights reserved. Keywords: Self-mutilation; Deliberate self-harm; Self-injurious behavior; Diagnosis; Personality disorder 1. Introduction Self-injurious behavior (SIB) refers to a broad class of behaviors in which an individual directly and deliberately causes harm to herself or himself. Such behavior can in- clude non-suicidal self-injury (NSSI), which refers to di- rect, deliberate destruction of one's own body tissue in the absence of intent to die; or suicide attempts, which refer to direct efforts to intentionally end one's own life. Some authors have noted the theoretical, methodological, and clinical importance of distinguishing among various forms of SIB (O'Carroll et al., 1996; Linehan, 1997); and these suggestions have been supported by empirical studies de- monstrating that self-injury-related constructs differ in their correlates (Nock and Kazdin, 2002; Nock and Kessler, in press) and functions (Brown et al., 2002). Although it is clear that NSSI and suicide attempts represent distinct behavioral phenomena, several important questions about Psychiatry Research 144 (2006) 65 – 72 www.elsevier.com/locate/psychres ⁎ Corresponding author. Tel.: +1 617 496 4484; fax: +1 617 496 9462. E-mail address: nock@wjh.harvard.edu (M.K. Nock). 0165-1781/$ - see front matter © 2006 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.psychres.2006.05.010