Key Areas of Brain Smaller in Alcoholic Teens

Newswise — Regions of the brain involved in complex thinking and emotional control are smaller in teens who abuse alcohol than in those who do not, according to a new study in the September issue of Alcoholism: Clinical and Experimental Research.

Researchers found significant volume differences in the prefrontal cortex, with an average volume of 157 ml for alcoholic teens and 176 ml for non-alcoholic teen controls. Average volume of prefrontal white matter was 50 ml for alcoholic teens and 61 ml for controls. (Five ml equals about one teaspoon.) Average volume measurements for the thalamus and cerebellum did not show significant differences for the two groups.

Scientists do not yet understand if the smaller size of those brain areas is a cause of alcohol abuse or an effect of it.

"Adults have to drink for many years to sustain any brain damage," says lead researcher Michael De Bellis, M.D, a professor of psychiatry and behavioral sciences at Duke University Medical Center. "We don't know exactly how alcohol affects brain development in adolescence but that is a very active time for such development, especially in areas that govern thinking, planning and emotional regulation. The adolescent brain might be much more vulnerable."

The research team used MRI scans to study the prefrontal cortex, the thalamus and the cerebellum in adolescents age 13 to 17 and in young adults 18 to 21. Fourteen subjects had an alcohol use disorder. Twenty-eight controls did not.

The researchers found no significant gender differences in the prefrontal cortex volumes. They did find that the cerebellum was significantly smaller in males who abused alcohol than in control males. Importantly, all the young people with drinking problems also suffered from one or more other mental disorders, usually including another substance abuse disorder.

The brain areas studied are ones that help people "put the brakes on" and "decide whether to do or not to do something," explains Maher Karam-Hage, M.D., assistant professor of psychiatry at the University of Michigan Medical School. "If those areas are smaller and hypofunctional, that might be part of the bigger theory of addiction," and help explain why people can't stop themselves from drinking even when they want to stop.

"For kids at risk of drinking, we need to start doing some prevention," Dr. De Bellis stated. "High-risk kids include any who have mental health problems before reaching their teens. Boys most often have attention deficit disorders and conduct disorders and girls usually exhibit depression and post-traumatic stress disorder, often related to abuse."

De Bellis MD, et al. Prefrontal cortex, thalamus, and cerebellar volumes in adolescents and young adults with adolescent onset alcohol use disorders and co-morbid mental disorders. Alcoholism: Clinical and Experimental Research 30(2), 2005.