This study replicates and extends prior work by examining how age of Non Suicidal Self-Injury (NSSI) onset relates to NSSI severity, suicidal behavior, perceived recovery from NSSI, and protective factors of life satisfaction, resilience, and subjective happiness. University students who reported engaging in NSSI within the past year (n = 644) completed on-line questionnaires assessing NSSI characteristics, suicidal behavior, and protective factors. Participants who began self-injuring at or before age 12 reported significantly more lifetime acts of NSSI, greater method versatility, and medically severe NSSI than those who began NSSI at older ages (17 years). Those with a typical age of onset (13-16 years) did not differ from the younger age group on method versatility, medical severity, past year frequency, or perceived recovery but did differ from those with an older age of onset. The proportion of individuals reporting suicide attempts significantly increased as the age of onset became younger. No age of onset group differences were observed on the protective factors. The age at which one begins NSSI appears to be a risk factor for increasingly severe NSSI and potential suicidal behavior. Early detection and intervention is important for reducing the negative consequences of engaging in NSSI.
Keywords: NSSI; Self-injury; protective factor; recovery; risk factor; self-harm; suicide.