Dopamine and alcoholism

Time magazine's science writer simplifies a recent study on neurobiology and alcoholism:

It's already known that addictive drugs, including alcohol, trigger a rush of dopamine. Getting that literal rush is such a powerful reward that it's a big part of the reason addicts go back to drugs, even though they know objectively that it's a truly bad idea.

Now comes a paper in the Journal of Neuroscience that adds another key piece to the addiction puzzle. Nora Volkow, director of the National Institute on Drug Abuse, long with several colleagues, used brain-imaging studies to look at the dopamine responses of alcoholics—not to alcohol, but to a different drug, methylphenidate, better known by its trade name Ritalin. In normal subjects, the drug causes a spike in dopamine in the brain's prefrontal cortex.

But in alcoholics, the study found, that spike is significantly muted. Says Volkow: "It could explain why alcoholics encounter a decrease in the ability to experience pleasure from everyday activities." In essence, they've been overstimulating their dopamine systems for so long with alcohol that their brains have become numb. It also explains why so many relapse into drinking; it's the one way they can experience any sort of pleasure.