Evaluation of Naltrexone as a Treatment for Self-injurious Behavior

Inclusion Criteria: * Thirteen years of age or older * Actively engaged in SIB at a rate of, on average, at least two events per week for at least 3 months * Has internet access in a secure and private manner * Lives within a reasonable distance from Kalamazoo (to make the five clinic visits convenient) and plans to remain in the area throughout the next 4-5 months Exclusion Criteria: * Under the age of 13 * Currently pregnant (confirmed with initial urine pregnancy test), lactating, or planning to become pregnant in the next 4 months * Active hepatitis or liver disease * Prior history of recently active opioid dependence * Current prescription, non-prescription, or illicit opioid use, (i.e., acute use within the past 14 days or chronic use within the last 30 days), including all opioid analgesics, certain cough and cold remedies (e.g., codeine), and certain anti-diarrheal preparations (e.g., loperamide). Currently taking an opioid antagonist for alcohol or opioid dependence or having taken one in the last 14 days * Current use of leflunomide (Arava), droperidol (Droleptan), diazepam (Valium), thioridazine (Mellaril, Novoridazine, Thioril) (26) * Any report of clinically significant medical condition or medication regimen which might cause undue risk or affect ability to participate in this clinical trial * On initial laboratory examination, alanine aminotransferase (ALT) or aspartate aminotransferase (AST) levels more than one standard deviation (SD) above the upper limit of normal * Unable to meet a 22-week requirement to log journal entries daily, to be available by phone a minimum of once weekly during the first month, and to be present at clinical sites once every three weeks for 12 weeks, for a total of 5 visits * Infrequent SIB, lack of secure Internet access, or living a significant distance from the Kalamazoo area (does not meet inclusion criteria) * Unwilling or parent/guardian unwilling to participate in research requirements.