Neuroimaging & Alcohol Craving

Many alcoholics experience an intense desire or "drug hunger" for alcohol known as craving.  Craving can be conceptualized as a biopsychosocial process that involves social cues that activate craving related brain responses.  These brain responses can be intensified or dampened by habitual ways of thinking, feeling, and behaving that are used to deal with the initial craving.  

Most researchers agree that craving involves a process of neuroadaptation.  The frequent, heavy, and long-term use of alcohol causes changes in brain cell function. Neuroadaptation produces an imbalance in brain activity that may make alcoholics more vulnerable to cues that activate craving.

Animal experiments suggest that craving is associated with certain brain regions and neurotransmitters.  Such experiments are limited by the animals' inability to report how they feel.  In humans, craving is experienced differently at different stages of alcohol addiction and differently among drinkers at any single stage.  As a result it is difficult to measure it accurately. To improve both measurement and understanding of the craving phenomenon, researchers are looking to new technologies in neuroimaging such as the fMRI technique.

Researchers at the Medical University of South Carolina (MUSC) used fMRI (functional magnetic resonance imaging) to examine whether alcohol cues stimulate specific brain regions.  There were two goals to their research: first, to learn whether certain brain areas would be activated for the alcohol cues but not the neutral cues; and second to determine whether brain areas in alcoholics would be activated differently than those of moderate drinkers.

The researchers recruited eight male and two female alcoholics and an equal number of moderate-drinking (no more than 14 drinks per week) controls matched according to age and gender. The alcoholics met DSM-IV criteria for alcohol dependence, drank an average of seven drinks per drinking day, and drank on about 70 percent of days in the month before testing. They were not severe alcoholics or in treatment at the time of study.

All 20 subjects viewed pictures on a screen while lying on their backs in a 1.5-Tesla MRI scanner. For nine minutes, they were shown a series of photographs of alcoholic beverages followed by a series of nonalcoholic beverages (e.g., coffee, juice, soda) in random order. To heighten their responses to alcohol cues, the subjects were given a sip of an alcoholic beverage before viewing the images. The researchers then compared the mean group images of brain activity during the alcohol and nonalcohol pictures.  

The results showed two things.  

    1.     When alcoholics view pictures of alcoholic beverages, their  prefrontal cortex and the anterior thalamus become active (These brain regions are associated with attention and emotional regulation and have been associated with craving in other studies).  The same brain activation does not occur when alcoholics view neutral pictures.  

    2.     When moderate drinkers view pictures of alcoholic beverages the same effect does not occur.  

This means that alcoholics have significantly different brain responses to alcohol-related pictures than moderate drinkers.  In other words, cues associated with alcohol use cause a specific brain response in alcoholics that is not activated by the same cues in moderate drinkers. 

This research reinforces the concept of alcoholism as a brain disease by demonstrating that craving is a biopsychosocial process associated with specific brain processes that are different in alcoholics and non-alcoholics and confirming that there is a significant biological and brain component to alcoholism.  

The lead author and Scientific Director of the NIAAA-funded MUSC Alcohol Research Center is Raymond F. Anton, M.D.  The findings are reported in the April Archives of General Psychiatry.