Variations in a particular gene may explain why some persons take to the bottle when they are stressed. Mice that lacked this gene began to drink three times more alcohol than normal mice after having undergone a stressful experience. They were still drinking appreciably more six months later. Such is the result of a German study conducted under the leadership of Rainier Spanagel from the University of Heidelberg.

The gene in question codes for CRH1, a type of receptor in the corticotropin-producing hormonal system in the brain. This system controls the hormonal and behavioural reaction to stress. The CRH1 receptor was previously suspected to be involved in psychiatric aberrations resulting from stress. “Patients with variations in this gene may be especially sensitive to stress and react to it by drinking”, says Spanagel.

Stress is the main cause of recidivism for many alcoholics undergoing treatment. This study of the underlying mechanism is therefore important and may assist efforts towards prevention and treatment. According to Spanagel, psychologists could help patients with variant genes by teaching them strategies for stress management.

During the research normal and mutated mice were first offered a choice between water and ethanol solutions at different concentrations. Both groups chose a solution with 8% ethanol. The mice were then exposed to two types of stress. The first type was caused by an attack by another mouse, the second type forced the mice to swim. Each stressing experiment took place over three consecutive days.

After the experiment both groups of mice continued to drink a normal amount of alcohol. But three weeks later the mutated mice suddenly began to drink much more alcohol. The effect was still present six months later. Spanagel is unable to indicate any cause for the interval of three weeks. He believes that the experiment with the mice provides a good model for human behaviour. More research is necessary regarding the effect of mutations in the gene CRH1 to understand and improve the behaviour of alcoholics.

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