A research team from Corella Drug Treatment Services and the University of New South Wales prescribed 500 milligrams of lithium twice a day for seven days to 20 people who were longtime, habitual cannabis users, the Sydney Morning Herald reported Thursday. After three months, most of the users were smoking cannabis less often. Many had given up completely, the newspaper said.

Chief investigator Adam Winstock said withdrawal symptoms for heavy pot smokers often include disturbances in mood and sleep, and hostility that can cause them to relapse. The National Drug and Alcohol Research Center estimates that one in 10 people who try marijuana will become dependent on the drug.