Brain opioid receptor binding in early abstinence from opioid dependence: positron emission tomography study.

BACKGROUND: Although opioid receptor function in humans is clearly reduced during opioid dependence, what happens to the receptor in early abstinence is not understood. AIMS: This study sought to examine changes in opioid receptor availability in early abstinence from opioid dependence. METHOD: Ten people with opioid dependence who had completed in-patient detoxification and 20 healthy controls underwent [11C]-diprenorphine positron emission tomography. Clinical variables were assessed with structured questionnaires. Opioid receptor binding was characterised as the volume of distribution of [11C]-diprenorphine using a template of predefined brain volumes and an exploratory voxel-by-voxel analysis. RESULTS: Compared with controls, participants with opioid dependence had increased [11C]-diprenorphine binding in the whole brain and in 15 of the 21 a priori regions studied. CONCLUSIONS: This study suggests that opioid receptor binding is increased throughout the brain in early abstinence from dependent opioid use. These data complement the findings in cocaine and alcohol dependence.