Significant differences among classes – means and standard deviations.

Note. Means in the same row with different superscripts are significantly different at p<.001. Higher scores indicate greater frequency of engagement in NSSI, age of most recent NSSI, pain during NSSI, time elapsed between urge to self-injure and act of NSSI, number of methods of NSSI, being alone during NSSI, more lifetime suicidal ideation/attempts, greater past year suicidal ideation, greater disclosure about suicidal behavior, and more likely to make a future suicidal attempt. Higher scores indicate greater daily hassles, difficulties with emotion regulation, depressive symptoms, self-esteem, social anxiety, behavioral inhibition, delinquency, friendship quality, parental attachment, parental criticism and parental psychological control. Scores on the SBQR range from 3–18, with a clinical cutoff score of 7. ***p<0.001.