Can a common drug curb Self-Harm? new trial aims to find out

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Participants must meet all of the following criteria: 1. Individuals aged 16 years or older. 2. Individuals with clinically significant nonsuicidal self-injurious behavior. 3. Individuals who are able to understand the study procedures and provide written informed consent. For minors, consent from a legal guardian and assent from the participant will be obtained according to applicable regulations. 4. Individuals who are able to comply with study procedures, including clinical visits, medication administration, and study assessments. 5. Women of childbearing potential must have a negative urine pregnancy test at screening and agree to use appropriate contraception during the study period. Exclusion Criteria: * Participants meeting any of the following criteria will be excluded: 1. Current serious suicidal ideation or high suicide risk, as determined by the investigator. 2. Current opioid use, opioid dependence, or use of opioid-containing medications. 3. Current use of opioid antagonists or medications that may interact with naltrexone, including methadone or buprenorphine. 4. Use of naltrexone within 1 week before screening. 5. Positive naloxone challenge test or positive urine opioid test, if applicable. 6. Known hypersensitivity to naltrexone or any component of the investigational product. 7. Active liver disease, active hepatitis, or clinically significant hepatic impairment. 8. Clinically significant renal impairment. 9. Pregnancy or breastfeeding. 10. Intellectual disability, organic brain disorder, or other condition that may interfere with the participant's ability to understand study procedures or complete assessments. 11. Inability to read or write Korean sufficiently to complete study assessments. 12. Documented prior non-response to naltrexone for nonsuicidal self-injury, as judged by the investigator. 13. Any other clinically significant medical or psychiatric condition that, in the opinion of the investigator, would make participation inappropriate or unsafe.