OBJECTIVE: Although nonsuicidal self-injury is a public health concern, there is little information on how it changes across adolescence or what contributes to stability or change. We aimed to identify trajectories of stability and change in self-injury from ages 13 to 17 years, and to identify interpersonal and intrapersonal correlates that differentiate between trajectories of stability and change.
METHOD: We used five annual waves of cohort-sequential data, targeting 7th and 8th graders attending all public schools in three municipalities in central Sweden. The data were gathered via questionnaires, using a multi-item measure of non-suicidal self-injury and assessing negative experiences at home, in school, with peers, and in romantic settings, as well as intrapersonal issues (internalizing symptoms and difficulties with emotional, and behavioral regulation). The analytic sample was 3195 adolescents (51.7% boys, 48.3% girls; ages 12-16 years at T1, M = 13.61; SD = 0.66), most of whom were born in Sweden (88.6%) to at least one parent of Swedish origin (77.4%).
RESULTS: Latent growth curve modeling revealed three self-injury trajectories: a stable-low, a low-increasing, and an increasing-decreasing trajectory. Adolescents in the stable-low class reported the best overall adjustment at ages 13 and 16. Comparatively, adolescents in the other two classes reported similar levels of difficulty interpersonally and intrapersonally. Where they differed, the increase-decrease class fared worse than the low-increasing class. CONCLUSIONS: This study suggests the need to frame self-injury as having multiple directions of development during adolescence and develop theory that aligns with differential patterns of self-injury development.