title: Unreinforced self-injections: effects on rituals and outcome in heroin addicts.
mesh_terms: D005108:Extinction, Psychological; D005500:Follow-Up Studies; D006556:Heroin Dependence / Q000188:drug therapy / Q000523:psychology*; D006801:Humans; D004091:Hydromorphone / Q000008:administration & dosage; D008297:Male; D009270:Naloxone / Q000031:analogs & derivatives*; D009271:Naltrexone / Q000627:therapeutic use*; D012054:Reinforcement, Psychology; D012107:Research Design; D012646:Self Administration
chemical_list: D009270:Naloxone; D009271:Naltrexone; D004091:Hydromorphone