~ Methadone has been used for the treatment of opioid addictions since the early nineteen-sixties. It is estimated that more than 200,000 individuals take methadone to control their opiate addiction (Blaney & Craig, 1999). Many of those individuals (~20%) have been in opioid-substitute treatment for 10 years or more (SAMHSA, 1994 about the effects of long term methadone use and its interaction with the physical, psychological and psychosocial aspects of the aging process. However, given the steady aging of the population in general and the methadone maintenance treatment (MMT) population in particular, there is a compelling need for a better understanding of the risks and benefits associated with the extended use of methadone in older adults.Beth Israel Medical Center (BIMC) has an extensive network of MMT clinics. The demographic profile of the clientele suggests that BIMC's clinics serve one of the largest populations of elderly methadone patients in the continental United States. We propose to conduct an exploratory study of BIMC's MMT population in order to document the prevalence of psychiatric, physical and psychosocial co-morbidities in the elderly members of that population (>=55 y/o). By comparing this profile with: (a) the profile of a representative sample of younger MMT patients (18-54 y/o); and (b) published prevalence data from the non-MMT, elderly population, we hope to identify areas of dysfunction and modes of adaptation that appear to be uniquely attributable to the interaction of long term methadone use and aging, and thus possible candidates for further and more extensive study.