A drug being used to treat alcoholism may have an additional benefit. It may also be a promising treatment for addiction to methamphetamine, an extremely addictive stimulant.
"The results were about as good as you could hope for," said lead author of the study Lara Ray, associate professor of psychology at University of California-Los Angeles (UCLA).
The study evaluated the efficacy of Naltrexone for treating methamphetamine addiction.
Researchers analysed 22 men and eight women who use methamphetamine an average of three to four days a week.
During a four-day hospital stay, each person was given either Naltrexone -- 25 milligrams the first two days, 50 milligrams on days three and four -- or a placebo daily.
The scientists found that Naltrexone significantly reduced the participants' craving for methamphetamine, and that it made them less aroused by methamphetamine:
Ray said the results indicated that Naltrexone reduced the rewarding effects of the drug -- those taking Naltrexone did not find methamphetamine to be as pleasurable and were much less likely to want more of it.
Naltrexone was well tolerated and had very minimal side effects. The researchers found that men and women both were helped by taking Naltrexone, although the positive effect on men was slightly smaller.
Methamphetamine use disorder is a serious psychiatric condition that can cause psychosis and brain damage, and for which no US Food and Drug Administration (FDA)-approved medication exists.
The study was published in the journal Neuropsychopharmacology.