Cerebral metabolism in opiate-dependent subjects: Effects of methadone maintenance

Background: The long-term effects of opiate use on human brain are not know n. The goal of this preliminary study was to determine whether human subjec ts with histories of opiate dependence have persistent differences in brain function as compared with individuals without substance use disorders, and whether methadone maintenance reverses or ameliorates the potential abnorm ality. Methods: Positron emission tomographic (PET) [18F]fluorodeoxyglucose (FDG) method was used to compare the regional cerebral metabolic rate for glucose (rCMRglc) in three groups: four opiate-dependent subjects currently receiv ing methadone maintenance therapy (MM), four opiate-dependent subjects not receiving methadone maintenance therapy (MW), and a comparison group of fiv e subjects without substance use disorders. Results: A significant difference in rCMRglc in the anterior cingulate gyru s was found between the MW and Control groups (Mann-Whitney U = 2.0, p = 0. 05). Generally speaking, rCMRglc's in MM subjects were intermediate between those of MW and Control groups, although the difference did not reach stat istical significance. Conclusions: The results of this study suggest that neurobiological abnorma lities can persist in the brain of a chronic opiate user several years afte r detoxification from methadone. Future research is needed to replicate the se results and to determine whether the observed rCMRglc differences are re lated to opiate use or to neurochemical abnormalities that play a role in d eveloping addictive behavior.