Assessing the Functions of Non-Suicidal Self-Injury: Factor Analysis of Functional Assessment of Self- Mutilation among Adolescents

The aim of this cross sectional study was to assess the factor analysis of Functional Assessment of Self- Mutilation (FASM) among Iranian adolescents with non-suicidal self-injury. In this study, 646 high school students, with the mean age of 16.55 ± 0.7, were selected using a multistage  cluster sampling method; they completed FASM and the demographic form. Data were analyzed using the descriptive statistics, chi-square (χ2), independent sample t test, MANOVA, and confirmatory factor analyses (CFA). Of the participants, 178 reported at least 1 episode of NSSI during the previous year. The mean age of the participants when they first harmed themselves was 14.64 (±1.71). Most of them reported to engage in NSSI impulsively (39.32%) and experienced little (31.5%) or moderate physical pain (31.5%) There were no significant differences between males and females in severity of NSSI, frequency of NSSI, thinking about NSSI prior to engaging in the act, and age of onset. The results of the confirmatory factor analysis supported the 4-factor model of NSSI functions suggested by Nock and Prinstine [Χ2/df = 1.84; RMSEA = 0.07; GFI = 0.82; AGFI = 0.77]. The most frequent function for engaging in NSSI was Automatic Negative Reinforcement . Findings of this study supported the structural validity of the FASM; thus, this tool can be useful in treatment and research contexts as a measure of NSSI functions. Moreover, this study found that adolescents engage in non-suicidal self-injury because of 4 distinct reinforcement processes. The study findings have important implications for the assessment and treatment of NSSI.