DeSanto suggested a different approach to John. To help work through the loss and grief he was feeling, counseling can help, she told him. She also recommended he try naltrexone, a prescription drug.

“Naltrexone is an effective medication for the treatment of alcohol use disorders,” says Koob. He points to a recent meta-analysis published in the journal Addiction that concluded that naltrexone helped reduce heavy drinking and cravings for alcohol.

The analysis included data from 64 clinical trials in which people were given either the medication or a placebo pill to test the effectiveness of the treatment. The analysis also found that another drug, acamprosate, is effective at helping people who have already stopped drinking to maintain abstinence, perhaps partly by easing the physical and emotional cravings experienced by heavy drinkers who quit.

So, how does naltrexone work? The drug seems to curb the euphoric and sedative effects of opiates in the brain. Alcohol is known to activate some of the same receptors in the brain that opioids do, and studies find that by tempering the pleasure from alcohol, naltrexone can help people drink less.