The Impact of Methadone Maintenance Therapy on Food Intake and Food Reward Processing in Opioid Dependence: An Event-related Brain Potential Study

Methadone maintenance therapy (MMT) has shown clear efficacy for relieving opioid withdrawal symptoms and reducing the morbidity and mortality of opioid dependence. A notable phenomenon associated with MMT is increased food intake, enhanced sweet preferences, and weight gain. The underlying neural mechanisms for opioid-related overconsumption are not well understood but are thought to arise from role in 1) increasing the palatability and hedonic aspects of food and 2) diminishing satiety signaling systems. In the proposed project, the investigators will examine methadone's potential role in opioid-related overconsumption of food. The investigators propose to examine eating behavior, sucrose preferences, and an event-related potential (ERP) component that is induced by appetitive motivation for highly rewarding foods in patients with a history of opioid dependence receiving methadone maintenance therapy (O+MMT) and not receiving opioid agonist therapy (O-MMT). A matched sample of obese and overweight adults without history of opioid use (HOC) will also be examined. Specifically, group differences in food intake and eating behaviors in the O+MMT group relative to individuals in the O-MMT and HOC group will be examined. Individuals will complete 24-hour dietary food recalls and inventories to characterize eating behavior and food addiction. Participants will complete psychophysical measures of chemosensory functioning of sucrose preference and pleasantness and identification ratings for odors varying in participants' hedonic characteristics. Individuals will also complete validated computer tasks to assess food preferences. Differences in cortical ERPs for high-reward food relative to low-reward food and non-food items will be examined. Event-related potentials will be recorded as participants view photos of rewarding and non-rewarding food items, as well as non-food items. ERP components that index sustained attentional engagement will be measured and compared.