Magazine article Science News

Brain Differences May Herald Drug Addiction

Magazine article Science News

Brain Differences May Herald Drug Addiction

Article excerpt

Differences in the behavior and the brain receptors of rats seem to predict which of the rodents will become cocaine addicted, scientists report. The finding supports the idea that some people are predisposed to drug addiction.

Scientists have long suspected that certain personality traits, including thrill seeking, impulsivity, and a tendency to be antisocial, go hand in hand with drug addiction. Studies have also shown that the brains of monkeys and people addicted to stimulants such as cocaine or amphetamine have significantly fewer receptors for dopamine, a brain chemical that regulates emotion, motivation, and feelings of pleasure.

However, the connection between these mental and physical characteristics and drug addiction has posed a chicken-and-egg problem for researchers. It's unclear whether drug addicts have these qualities before they begin using drugs or whether taking drugs over the long term changes a person's personality and brain properties.

Jeffrey Dalley of the University of Cambridge in England and his colleagues report results in the March 2 Science that shed light on this problem. The researchers taught a group of lab rats to poke their noses in a hole to retrieve a treat after seeing a light flash. The team found that about 7 percent of the animals consistently acted impulsively. Rather than wait to collect the treat that appeared after the light blinked, those animals frequently poked their noses into the hole before the treat arrived.

Dalley's team next scanned the rats' brains. …

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