This study is using blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) to examine the brain predictors of adherence and outcomes of opioid antagonist therapy. Opioid-dependent intravenous heroin users are offered up to 3 monthly injections of the extended-release naltrexone (XRNTX) contingent upon successful outpatient non-opioid detoxification, with an additional 4 weeks of follow up. Brain responses to heroin-related pictures are recorded using fMRI prior to the 1st XRNTX injection and approximately 2 weeks thereafter the 1st XRNTX injection. Primary clinical variables include the number of injections (maximum of 3) accepted by participants, change in self-reported craving for opioids after exposure to drug-related visual cues during the brain fMRI sessions, urine levels of ten commonly abused substances and self-report of cigarette use.
