Longitudinal development of non-suicidal self-injury disorder in adolescence: Prospective prediction of stability and change by identity development, depression, trauma, and resilience.

BACKGROUND

With the introduction of non-suicidal self-injury disorder (NSSI-D) in DSM-5, the field obtained a standardised set of criteria to study those engaging in more severe and chronic NSSI. To date, no previous research has studied the development of NSSI-D longitudinally, leaving questions on its stability and potential prospective predictors unanswered.

METHODS

2162 community adolescents (M = 15.00 years, SD = 1.88, 53.9 % girls at T1) completed a set of self-report questionnaires for three consecutive years and were classified into three severity-based NSSI subgroups (no-NSSI, subthreshold-NSSI, NSSI-D). Multinomial logistic regression analyses were used to prospectively predict subgroup membership by age, gender, identity development, depressive symptoms, traumatic experiences, and resilience.

RESULTS

At baseline, the sample was distributed over the no-NSSI group (88 %), the subthreshold-NSSI (6 %) and NSSI-D (6 %) groups. These groups respectively showed high (93.5 %), low (25 %) and moderate (47.5 %) stability over one-year intervals. Longitudinally, higher levels of identity confusion and trauma significantly increased the likelihood of transitioning to subthreshold-NSSI. Moreover, boys had a higher likelihood of transitioning from NSSI-D to no-NSSI over the course of one year.

CONCLUSIONS

This three-year study provides the first indication of the longitudinal course of NSSI-D with the current set of DSM-5 criteria. Clinically, the results suggest the particular potential of identity confusion and trauma as prevention targets in community adolescents.