Nonsuicidal self-injury (NSSI) is highly prevalent among adolescent and emerging adult females. Most studies examining the relationship between stress and NSSI largely have relied on aggregate self-report measures of stress and between-person models. Using data from two prospective samples, this manuscript tests the hypothesis that within-person models of NSSI provide better clinical markers of risk for NSSI than between-person models of NSSI.
Two samples (Sample 1: 220 high-risk girls, M age = 14.68, SD = 1.36, baseline assessment and 3-month follow-ups for 18 months; Sample 2: 40 emerging adult females with a history of NSSI, M age = 21.55, SD = 2.14, 14 days with daily retrospective reports) were followed prospectively and completed validated measures of stress and NSSI. Models were adjusted for age and depression.
In Sample 1, a within-person model demonstrated that higher-than-usual (but not average) stress levels predicted NSSI within the same 3-month wave. In Sample 2, results from a within-person model with daily diary assessment data showed that higher-than-usual stress (but not average daily stress) predicted same-day NSSI.