Recovering alcoholics might be able to repair some of the damage drinking has done to their brains if they quit soon enough, European researchers say.

"The core message from this study is that, for alcoholics, abstinence pays off and enables the brain to regain some substance and to perform better," said Andreas Bartsch, a neuroradiologist at the University of Wuerzburg, in Germany.

"However, it also shows the longer you drink excessively, the more you risk losing this capacity for [brain] regeneration. Therefore, alcoholics must not put off the time when they decide to seek help and stop drinking. The sooner they do it, the better."

In the January issue of the journal Brain, Bartsch and his colleagues report the results of their study, which used MRIs to measure the brain volume of 10 alcoholic men and five alcoholic women.

The researchers also measured levels of a chemical that signals brain power. And study participants were given tests of their concentration.

The team also looked at 10 healthy volunteers, matched for age and gender, as controls. Brains of alcoholics were scanned before and after they stopped drinking without medication.

After 38 days off the bottle, brain volume increased by an average of nearly two per cent, the team found. Study subjects also performed better on the tests of their concentration.

"Only the one patient with the longest history of alcohol dependence had a slightly reduced brain volume," said Bartsch.

The findings unify several previously separate lines of research and may help doctors to motivate alcoholics to stay sober, said Graeme Mason, a professor of diagnostic radiology at Yale University in New Haven, Conn., in an accompanying commentary.

"Doctors treating or studying alcoholism should be made aware of the research of Dr. Bartsch because it may provide a motivational tool that is a broad set of concrete, tangible, and rapid benefits of sobriety: cognition, chemistry and brain volume," Mason wrote.

"Patients often become discouraged from the physical and cognitive difficulties of achieving and maintaining sobriety."