Authors: Barry Everitt (University of Cambridge, UK)
Barry Everitt is Emeritus Professor of Behavioral Neuroscience at the University of Cambridge (UK), where he has been for 40 years. He is also the Provost of the Gates Cambridge Trust (University of Cambridge), which is dedicated to fund international graduate students who come to study at the University of Cambridge. Barry is also the President-Elect of the Society for Neuroscience.
In this interview, Barry speaks to us about his talk at the BNA Festival of Neuroscience (14–17 April, Dublin, Ireland) on ‘Addiction: a compulsive interplay between drugs, cues and habits’. Barry also discusses what neuroimaging studies have revealed about addiction, including how we might overcome current challenges in the field.
1.You presented a plenary session at the BNA Festival of Neuroscience on addiction – could you provide us with an overview about this?
I presented research from our laboratory to which many have contributed, which aims to understand the neural and psychological mechanisms that are involved in the process of becoming addicted to drugs. This has a fundamental premise that people take drugs initially because they’re rewarding. There’s a lot of work to suggest that this rewarding effect of drugs for very different classes depends upon profound activation of the dopamine reward system in the brain.
There are multiple lines of evidence that demonstrate this however, I’ve argued that a major challenge in understanding addiction is how some people gradually lose control over that initial, voluntary or recreational, drug use so that they develop habitual use that eventually becomes a compulsion to seek and use them.
Let’s take a simple example of drinking alcohol. Many of us will begin by having an occasional drink and easily this can become two or three glasses of wine or pints of beer in an evening. This is nowhere near being addicted, but certainly is in the realm of problem use, which is harmful and can become habitual. But in a small group of people (estimated at approximately 20%) this use escalates, cannot be controlled and they become compulsive in their pursuit of and use of alcohol. They can’t stop drinking despite really serious negative outcomes, including physical harm, damage to health, damage to family and, in the case of illicit drugs, the risk of incarceration. Probably, their response to alcohol from the very outset was different to the majority of people and so they were always vulnerable to lose control.
I work experimentally on addictive behavior in animals and while the subjective states induced by drugs (highs) cannot really be studied in these models, it is possible to study their behavior – their seeking and taking of drugs and these are amenable to neurobiological and psychological analysis. Our premise is that initially, when people seek and take drugs their behavior is under goal-directed control – it is purposeful and is so as to experience the mood and feeling-orientated effects of the drug.
However, over time the seeking and taking of drugs is elicited automatically by the stimuli in the environment that have been associated with the effects of the drugs from the very earliest drug-taking experience through Pavlovian conditioning. This is the notion of drug-seeking and -taking habits; it becomes increasingly situational and not so readily under voluntary control.