Once an alcoholic, always an alcoholic—the saying is decades old, but scientists have only recently uncovered why it is often true. Long-term alcohol abuse changes the brain, making a person more sensitive to stress and more likely to reach for the bottle to soothe his or her anxiety. According to a March 14 study in the journal Science, drugs that inhibit these stress pathways could help recovering alcoholics stay in control.
Scientists at the National Institutes of Health and University College London bred mice lacking the neurokinin 1 receptor (NK1R), a protein involved in the brain’s stress response. The mice were given unlimited access to alcohol-spiked water for 60 days, during which the alcohol content was incrementally raised from 3 to 15 percent. The NK1R-deficient mice consumed far less alcohol—especially later in the trial when alcohol concentration was higher—than the normal mice did. They were also more sensitive to alcohol’s effects than the normal mice were; studies have shown that the more sensitive a person is to alcohol, the less likely he or she is to abuse it.
The team then treated 25 highly anxious recovering alcoholics with a drug that blocks the NK1 receptor. After four weeks of hospital treatment, the subjects taking the drug reported fewer spontaneous and stress-induced alcohol cravings than patients given a placebo did. When the scientists used functional MRI to look at the subjects’ brain activity, they found that the treated subjects showed less activity in the insula, a region associated with craving. The scientists believe the drug targets a stress pathway specific to alcoholics because it has been shown to have little effect on stress levels in other types of patients.
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Lead author Markus Heilig of the NIH cautions that although the study is promising, it does not prove that the drug will help alcoholics long-term. Scientists “need to do studies in outpatients and look at reduction in drinking,” he says. A larger clinical trial designed to do just that will begin recruiting subjects later this year.
Editor's Note: This story was originall printed with the title "Ease Anxiety, Curb Cravings"
