The specific objectives for this extension of the LAAM safety and efficacy study is to gain further information on the use of 1-alpha- acetylmethadol in the maintenance treatment of opiate addicts. Specifically, it is proposed to give the 10 LAAM maintenance patients currently on the study the option of continuing on LAAM maintenance for an additional 40 weeks after these patients conclude their initial 40 weeks of LAAM maintenance. Additionally, it is proposed to give the 11 currently active methadone maintenance control group patients the opportunity to (1) shift to LAAM maintenance for a period of 40 weeks or (2) continue as methadone maintenance control patients for an additional 40 weeks of study. Additionally, it is proposed to enlist 15 female methadone maintenance patients of non-childbearing potential as study patients for LAAM maintenance for a period of 40 weeks. Moreover it is proposed to enlist 15 female patients, currently on methadone maintenance, as a control group of study patients to be used for purposes of contrast with the group of female LAAM maintenance patients. During this extended study of LAAM it will be possible to gather baseline information from periodic physical examinations and laboratory tests to further document the safety of LAAM in human subjects. Thus, it seems likely that this study will include 10 male patients who elect a second 40 week period of LAAM maintenance, 11 methadone control group patients who elect a 40 week period of LAAM maintenance, 15 female patients of non-childbearing potential who elect a 40 week period of LAAM maintenance as well as a group of 15 female patients who will serve as a control group on methadone maintenance for the 40 weeks of the study. Further data will be gathered on the efficacy of LAAM as a substitute for methadone through the definite inclusion of the 15 female LAAM maintenance patients in this study as well as through the inclusion of the 11 patients from the methadone control group who have generally indicated their preference for shifting to a 40 week period of LAAM maintenance.