The stress hormone cortisol may be useful in treating heroin cravings, a new study suggests. Swiss researchers found cortisol decreased cravings in heroin patients by up to 25 percent.

Cortisol is secreted in response to stressful situations. The study included 29 people addicted to heroin who were undergoing treatment with pharmaceutical heroin, which is legal for use in some countries. They received either a cortisol tablet or a placebo before receiving a dose of heroin. They were later asked to rate their cravings.

Patients taking a low dose of heroin (up to 305 milligrams daily) reported having much lower cravings for another dose after taking cortisol, compared with those taking a placebo. Cortisol did not lower cravings in those taking a higher dose of heroin, Newsweek reports.

The findings appear in Translational Psychiatry.

Lead researcher Dominique de Quervain of the University of Basel said cortisol might be useful in treating other types of addictions. “It might be interesting to see if [cortisol] also works for other addictions — for example, nicotine or gambling — because they are all driven by craving,” de Quervain said.

He explained that cortisol levels increase significantly under stressful conditions. He said that just as the stress of taking a test can cause students to forget what they have learned, increasing cortisol levels might wipe a heroin user’s “addiction memory.” He added, “What we think is that cortisol, by reducing addiction memory, can actually also reduce craving.”

De Quervain said clinical trials are needed to assess the safety and effectiveness of cortisol as a treatment for addiction. Plans are already underway for further research on cortisol and addiction, according to a university news release.