- Methadone, a synthetic opioid agonist, is commonly used for the treatment of heroin dependence. Depending on how alcohol addiction is defined, rates of alcoholism vary among those attending methadone maintenance treatment (MMT) programmes. Most of the current literature has shown that alcohol consumption increases during medium- or long-term MMT. However, up to now, no data have been reported on changes in alcohol intake among a population of heroin addicts with no alcohol-dependence diagnosis after short-term methadone administration. Thus, the aim of our study was to investigate alcohol consumption changes in a population of non-alcoholic heroin addicts during the first 4 weeks of a treatment programme (TP). The TP consisted of either MMT or non-methadone maintenance treatment (N-MMT) with a minimum duration of 1 year. A total of 359 heroin-addicted out-patients [274 males (76.3%)], all of whom met DSM-IV criteria, were enrolled in the study, over a period of 4 months. Out of these 359 patients, 32 subjects (8.9%) dropped out, whereas 327 subjects (91.1%; 249 males) continued the TP [105 (32.1%; 78 males) in the MMT group and 222 (67.9%; 171 males) in the N-MMT group]. A significant reduction in daily alcohol intake was observed in the MMT group, but not in the N-MMT group after the first 4 weeks of the TP. The results of the present study suggest a possible effect of short-term methadone administration in reducing alcohol consumption in a population of non-alcoholic heroin-addicted patients.