Different people drink alcohol for different reasons. Knowing someone’s motivation can help researchers develop more personalized treatments for problematic drinking. Studies show that reward drinkers, those who say that drinking makes them feel good, behave differently from relief drinkers, those who drink because it makes them feel less bad (i.e., they are self-medicating or alleviating withdrawal symptoms).
In a recent study, we aimed to explore whether these two categories of heavy drinkers also showed differences in their brains. Specifically, do reward and relief drinkers have different patterns of neural activation when looking at pictures of alcoholic beverages?
To answer this question, we recruited people who drink heavily and categorized them into reward- and relief-drinking groups using the Reward/Relief/Habit Drinking Scale and the Reasons for Heavy Drinking Questionnaire. Previous research suggested that while most people begin drinking for positive reinforcement (reward), as they continue to drink heavily for a long period of time, they begin to drink out of negative reinforcement (relief).
We also knew that the ventral striatum is a brain region associated with reward, while the dorsal striatum is associated with compulsive behavior. Therefore, we hypothesized that reward drinkers would have greater neural activation in the ventral striatum while looking at images of alcoholic drinks, whereas relief drinkers would have greater activation in the dorsal striatum when viewing these images.
We found that relief drinkers did indeed show significantly more activation in the dorsal striatum. However, contrary to our hypothesis, there was not much difference between reward and relief drinkers in the ventral striatum. We interpreted this to mean that the rewarding qualities of alcohol may not be lost in relief drinkers, but that a sense of relief may be gained in addition to the reward.
This study showed that there might be biological differences underlying different motivations for drinking, which opens the door to further development of precision medicine to treat alcohol addiction. One next step in this line of inquiry might be to examine differences in reward and relief drinkers’ response to existing treatments.