1. Deliberate self-injury involves deliberately damaging body tissue without suicidal intent in order to relieve negative emotions. It is commonly seen in people with borderline personality disorder, PTSD, depression and other mental health conditions. 2. The neurobiology of self-injury involves 5 phases - perception of threat leading to a negative emotion, choosing self-injury as a coping mechanism, the act of self-injury, an unknown mechanism of action that provides relief, and the experience of tension relief. 3. During self-injury, the brain's serotonin system and prefrontal cortex-limbic connections are involved, along with activation of the endogenous opioid system which can reduce pain sensitivity and increase opioid