Alcohol Harms Teen Brains: Medical Effects of Drinking

We often hear that alcohol harms teen brains. Does drinking in adolescence harm brain growth? Will having alcohol before age 21 cause brain damage? Does underage drinking retard mental development?

Government agencies, activist groups, and news reports warn us that drinking alcohol harms teen brains.

The Evidence that Alcohol Harms Teen Brains

The evidence comes from two sources.

(1) The first is from lab rats. Researchers give young rats very large doses of alcohol. And large enough amounts of alcohol given long can cause brain impairment in them.

A serious problem is that rats aren’t humans. And many if not most processes found in rats don’t apply to humans. For example, many drugs cure diseases in rats. Yet most of them don’t do so in humans.

(2) The second source of evidence comes from humans. However, the humans who are studied are alcohol and/or drug addicted. Not surprisingly, long-time alcohol abusers tend not to do as well on many mental tasks.

So large enough amounts of alcohol can impair brain development in rats. It can also do the same in humans. There’s no surprising news there.

alcohol harms teen brainsThese studies never deal with light or moderate alcohol drinking among young humans.

Yet “natural experiments” on drinking among young people exist. And they’ve been going on for thousands of years around the world.

In many societies most people drink. They begin doing so in the home at a very early age. Examples include Italians, Jews, Greeks, Portuguese, French, Germans and Spaniards.

There is no evidence that members of these groups are brain impaired. Nor is there any reason to suspect it. In fact, they do well on standardized tests of mental ability. Certainly when compared to those in societies prohibiting young people from drinking.


There is no evidence that the light or moderate consumption of alcohol harms teen brains.

Good News

Research funded federally finds that teens who drink alcohol with their parents are less likely to abuse alcohol. That’s reported by a nation-wide study of over 6,200 teenagers in 242 communities across the US.

Drinking alcohol with parents “may help teach them responsible drinking habits or extinguish some of the ‘novelty’ or ‘excitement’ of drinking.” That’s according to senior researcher Dr. Kristie Long Foley of the School of Medicine at Wake Forest University. Dr. Foley describes drinking with parents as a “protective” behavior.

Research from other countries confirms these results.

Contrary to popular belief, drinking with parental approval is legal in many states across the country. Only seven states prohibit those under age 21 from drinking under all circumstances.

So drinking alcohol harms teen brains? No, but drinking with parents reduces alcohol abuse. And research in many countries shows it.

Needless to say, no one of any age should ever abuse alcohol.