ADDICTION LINKED TO BRAIN'S DECISION-MAKING CENTER

NEW YORK (Reuters Health) - Some people who are addicted to alcohol or
drugs may have problems with their decision-making skills, researchers
suggest. Their findings give weight to the idea that addiction involves a
flaw in the brain's decision-making center.

In a study conducted at the University of Iowa in Iowa City, a majority of
alcoholics and drug addicts scored as poorly on a test measuring the
ability to make decisions as people with damage to a brain region that
helps control decision-making.

People who abuse alcohol or drugs often behave similarly to people who have
experienced damage to a part of the brain called the ventromedial
prefrontal cortex (VM), which is involved in decision-making. For instance,
both groups of people often deny they have a problem or are unaware of it.
And when given a choice to do something that will bring them immediate
pleasure but will lead to negative consequences later, they often opt for
instant gratification.

A test called the Iowa Gambling Task, which simulates real-life decisions,
can detect malfunctioning in the decision-making in people with this type
of brain damage. To see how alcoholics and drug abusers would fare on the
test, Dr. Antoine Bechara and colleagues studied 41 substance abusers, 5
patients with VM damage, and 40 healthy people.

Considerably more alcoholics and drug abusers than healthy people fared as
poorly on the test as those with brain damage, the researchers report in a
recent issue of the journal Neuropsychologia. Sixty-one percent of addicts
scored as poorly as brain-damaged patients, compared with only about 33% of
healthy participants.

Several factors--including age, sex and educational background--did not
predict which people with substance abuse problems would score poorly on
the test, the report indicates. However, substance abusers who were able to
hold down a job tended to score better.

The results of the study support the idea that addiction to drugs or
alcohol is somehow linked to poor decision-making, Bechara and his
colleagues conclude. But they doubt that all substance abusers have flawed
decision-making skills, since not all of them scored poorly on the gambling
task.

"However," they write, "at least a substantial subgroup of (substance
dependent individuals) shows severe decision-making impairment, and this
deficit may contribute to their substance dependence problem."

The findings may help explain why not everyone who tries alcohol or drugs
becomes addicted, Bechara pointed out. Most people choose not to repeatedly
do things that have led to punishment, either financial or social, he noted
in a statement. People addicted to drugs or alcohol, however, may not be
able to resist the promise of immediate reward, Bechara suggested.

The researchers note that it is possible that alcohol or drug abuse may
itself somehow damage the brain, leading to decision-making troubles.

SOURCE: Neuropsychologia 2001;39:376-389.