The therapeutic process is highly structured and is divided into several phases of treatment for opiate addiction. These phases are the intensive stabilization phase, the commitment phase, the rehabilitation phase, the medical maintenance phase, the methadone tapering phase, and the reinforcement phase. Some individuals are placed in a transitional phase if they repeatedly test positive for opiates or other drugs but who also express a desire to remain in treatment. The phases-of-treatment model facilitates the development of a range of components within methadone treatment programs, based on a biopsychosocial staged approach to treatment. The model also provides a framework for determining staffing patterns, training methadone treatment staff, and aiding the development of performance-based standards for program evaluation and quality assurance. Figure, table, author photos and biographies, and 61 references (Author abstract modified)