‘Feel good’ endorphins may be activated differently in the brains of social drinkers as compared to problem drinkers, according to recent neuroscience research. These insights may lead one day to finding more effective drugs to treat problem drinking.
Some unusual findings coming out of a study recently published in the journal Science Translational Medicine, might help explain why some alcohol users become problem drinkers. A team of researchers led by neuroscientist Jennifer Mitchell at the University of California used Positive Emission Tomography (PET) scans to monitor certain brain activities in human subjects following their consumption of alcohol. PET scan images of the brains of problem drinkers were then compared to those of social drinkers. The researchers were particularly interested in how alcohol consumption affects the release of endorphins in two particular regions of the brain: the nucleus accumbens and the orbitofrontal cortex. Endorphins are chemical compounds produced in the pituitary gland; they mimic the action of opiates and produce feelings of pleasure, well-being, and relief from pain.
Results of the study showed that both groups of drinkers reported subjective feelings of intoxication after consumption, and their blood alcohol levels did not differ significantly. There were no differences between the groups with respect to the subjective perception of intoxication and the degree to which endorphins were released in the nucleus accumbens region of the brain. But among the problem drinkers there was a positive correlation between the subjective perception of drunkenness and the degree of endorphin release and binding in the brain’s orbitofrontal cortex.
In part, these findings suggest that problem drinkers might experience a subjectively greater “high” compared to social drinkers as the result of increased endorphin activity in critical regions of their brains. This might at least partly account for their propensity to drink greater amounts of alcohol than social drinkers.
Researchers have long known that the release of endorphins plays a role in a variety of addictive behaviors. And studies conducted on animals have demonstrated that the release of endorphins increases ethanol consumption. There is also some evidence that altered endorphin release contributes to problem drinkers’ tendency to drink more than non-problem drinkers in order to to feel the same subjective level of euphoria. Moreover, certain medicines used in the treatment of alcoholism may be effective because of their ability to modify the binding of endorphins to certain brain receptors, thus alteing a person’s perception of well-being. Learning more about how the consumption of various substances is triggered by the production of the body’s natural opiates, in which areas of the brain greater endorphin binding occurs, and how other chemicals influence both the release and binding of endorphins will likely lead to the development of new and more effective drugs to treat alcoholism and other addictions.
Alcoholism is a major illness that affects tens of millions of individuals worldwide (estimates range as high as 20 million in the US alone). And alcohol can take adverse control over many areas of a person’s life, including their relationships. It can also lead to various additional medical problems, including liver damage, memory loss and other cognitive dysfunction, depression, inflammation of the pancreas, high blood pressure, and digestive tract bleeding, to name only a few. The total cost to society in terms of lost productivity, alcohol-related accidents and injuries, and necessary treatments is estimated to be in the tens of billions.
Most experts regard alcoholism as a terminal disease because unchecked and untreated, the long term effects on a person’s critical body systems most often lead to death. And presently, there is no “cure,” although the disease can be held in check with proper treatment. Nonetheless, alcohol addiction is a tough adversary, and many individuals who undertake treatment relapse. That’s why the search for better ways to manage or possibly even cure the disease continues in earnest. Dr Mitchell does not claim that the findings in her study represent a breakthrough in the search for a cure. But her team has added yet another piece of the puzzle with respect to the link between alcohol consumption and users’ subjective experience of pleasure, and that could well lead to the development of more effective drugs to treat problem drinking.
Jennifer M. Mitchell, James P. O’Neil, Mustafa Janabi, Shawn M. Marks, William J. Jagust and Howard L. Fields (2012) ‘Alcohol Consumption Induces Endogenous Opioid Release in the Human Orbitofrontal Cortex and Nucleus Accumbens’, Science Translational Medicine 4: 116.