Opioid addiction is a major health challenge with death rates at an all-time high. In 2018 England and Wales had the highest annual increase (16%) in drug-related deaths since records began and over half of these deaths (51%) involved an opioid [1].
A key challenge in treating opioid addiction is preventing relapse once a person is abstinent. Opioid substitution therapies (OST) such as methadone and buprenorphine are commonly used therapeutically, alongside psychosocial therapy, to try and prevent relapse and minimise harm to the individual.

Chronic opioid exposure is associated with a range of physiological symptoms including impaired respiratory function, cardiovascular disorders and severe and lethal sleep disorders. We also see impaired cognitive function including reduced performance in inhibitory control, verbal working memory, decision making and emotional and reward processing . As a result, there is now a drive to achieve abstinence. However, abstinence can be difficult to achieve due to the range of withdrawal effects associated with cessation of opioids. These include but are not limited to muscle aches, sweating, sleep disturbances and craving. These symptoms often perpetuate drug use and can lead to relapse.

We have previously shown that Aprepitant, an NK1 receptor antagonist, ameliorates impairments in fronto-striatal network response during reward, inhibitory control and emotional processing in abstinent drug and alcohol dependent participants. In our current study, Neural Correlates of Reward and Emotion in Opioid Dependence (NCORE) we aimed to identify brain processes of reward and emotional processing in opiate dependence, during methadone maintenance. We also sought to investigate the modulation of these processes by NK1 antagonism and evaluate its potential as a therapeutic target to facilitate opiate detoxification and/or improve relapse prevention in early abstinence.