If the Genes Fit....

U.K psychiatrists agree addiction is "genetically determined."

Although the verdict is very little in doubt these days, the heritability of addictions was reaffirmed by the U.K.'s Royal College of Psychiatrists in London on July 4th.

In a presentation at the group's annual meeting, held at Imperial College, Professor Wim van den Brink of the University of Amsterdam's Academic Medical Center pinned the blame for addiction squarely on the absence of a sufficient number of dopamine receptors in the brain. "Addicts find it difficult to receive pleasure," he said. "They are not likely to enjoy most of the ordinary things most of us enjoy... they are looking for more stimulus."

Professor van den Brink also made clear the importance of environmental interactions for gene expression: "You might start off smoking or taking cocaine, and that first introduction is very much determined by your environment. But to stick with it and become dependent on it is genetically determined."

The self-defeating nature of addiction is graphically illustrated by the overall decrease in the number of pleasure receptors for dopamine and serotonin over time, as drug use escalates. Moreover, addicts show a striking deficiency in the ability to engage in long-term thinking. This behavioral link, the Royal College maintained, is the reason addicts fail to realistically differentiate between short-term pleasure and long-term negative effects.

This inability of drug addicts to engage in effective long-term thinking is well summarized in the old Reverend Gary Davis song: "Cocaine's for horses and it's not for men/Doctor said it kill you, but he didn’t say when."

Photo Credit: National Institute on Drug Abuse

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