Want to get sober? Harvard researchers analyzed data on 10,565 people to figure out how

Twelve Step programs work—but some are much more effective than others.

A new review of 27 studies covering 10,565 participants concludes that the key to sobriety is a 12-step program that is based at a clinic. These programs are typically facilitated by a professional and adopt some principles of Alcoholics Anonymous (AA). Their one-year sobriety rate is astonishingly high at 42%.

“It does matter what type of Twelve Step Facilitation intervention people receive,” says coauthor Dr. John Kelly, a professor of psychiatry at Harvard Medical School. “Better organized and well-articulated clinical treatments have the best result.”

Avoid looser programs where a counselor is winging it once a week. The study suggests that successful programs follow standardized procedures and are designed to increase long-term AA participation. Not surprisingly, the researchers attribute the sky-high success rate to the fact that people in these programs tend to join AA long term.

For those unable to swallow the religious undertones of AA, the researchers found that the next most effective treatment is cognitive behavioral therapy, which had a 35% sobriety rate after one year, though it is exponentially more expensive than AA, requiring ongoing one-on-one appointments with a psychotherapist.

The research is an update to a 2006 paper that reviewed eight studies with a smaller number of participants.