KEY POINTS:
Alcoholics will in future be offered gene testing to target them with the treatment best suited to their genetic make-up, a leading researcher has told an Auckland conference.
Professor Charles O'Brien of Pennsylvania University in the United States said yesterday that genetic testing was at present a research technique, but would become standard clinical practice.
Professor O'Brien told around 700 people at an addictions conference in Auckland that alcoholism had a hereditary component and researchers had not identified the many genes that would be involved in the complex behavioural condition.
Genetic variation had been found, however, that was associated with one aspect of alcohol consumption - the particularly strong response experienced by some when they drank, "making them feel super-good".
The genetic type, called the Asp40 variant - of which at least one copy is thought to be present in 24 to 36 per cent of people of European descent - did not force the person to become an alcoholic.
"It increases their risk of drinking a lot of alcohol. If they become an alcoholic, they are likely to respond to treatment that blocks their opiate receptors," he said.
Opiate receptors are proteins on nerve cells activated by endorphins, a brain hormone, after alcohol consumption. This produces the euphoria associated with alcohol.
Naltrexone is a drug that blocks the opiate receptors, preventing the body from responding to alcohol in the usual way. It reduces cravings for alcohol in some patients.
Professor O'Brien's group checked rates of relapse - returning to drinking at hazardously high or hazardously regular levels - of two groups of people with the genetic variation, one given naltrexone and the other a placebo.
At three months, around 50 per cent of the placebo group had not relapsed, compared with about 85 per cent of the naltrexone group.
When that study was published in 2003, he and his colleagues wrote that if the findings could be replicated in later research, the genetic variation could be used to select the patients likely to do well on naltrexone.
He told the conference that the findings would be published next February.
