BackgroundAlthough opioid receptor function in humans is clearly reduced during opioid dependence, what happens to the receptor in early abstinence is not understood.AimsThis study sought to examine changes in opioid receptor availability in early abstinence from opioid dependence.MethodTen people with opioid dependence who had completed inpatient 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.ResultsCompared 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.ConclusionsThis 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.