The goal of this study is to evaluate the efficacy and safety of the dietary supplement N-Acetylcysteine in adolescents aged 13-21 with deliberate self-harm behaviors. There will be an additional neuroimaging component to expand knowledge regarding the neural correlates of this treatment in the study population. We hypothesize that N-Acetylcysteine will reduce the severity of deliberate self harm behaviors because this supplement has been helpful in treating disorders that share some similar traits with DSH. We will be using this medication in 40 young people who deliberately harm themselves and we will assess the severity of their behaviors while being treated with this dietary supplement. We also will collect neuroimaging data on the study participants at baseline and after the treatment with N-Acetylcysteine and compare it to 40 age-matched healthy peer neuroimaging data. The purpose of including this healthy group is to expand knowledge about neural correlates of the study population prior to treatment.