"The majority of people in the nabiximols group either stopped using or dramatically reduced their use, maybe down to two, three, four days a month, whereas in the placebo arm, we found many people continued to use most days - four, five, six days out of seven," he said. Loading The results were even starker when the researchers looked just at the proportion of people who were able to reduce their cannabis usage by 50 per cent or more. "Almost over twice as many people had made that change in the nabiximols arm, so there was quite a significant difference between the groups," Professor Lintzeris said. Cannabis is the most widely used illicit drug in Australia, according to the Australian Institute of Health and Welfare. Professor Lintzeris said cannabis dependence was "quite common" so this research was significant as it was the first time researchers had linked medication with counselling to help reduce cannabis dependence.

Professor Michael Farrell, from the National Drug and Alcohol Research Centre, said the study was an "important contribution" to development of cannabis dependence treatment and it deserves further research. "The findings are positive but modest," he said. "We’re not looking at some radical effect, but it does provide an important conceptual discussion of ways we might consider this type of treatment into the future." Professor Farrell and Professor Lintzeris both pointed out the cost of nabiximols - licenced in Australia for the treatment of multiple sclerosis at the cost of about $745 for six to eight weeks of treatment, according to MS Australia - was one drawback of the potential treatment. "I think it needs more research before it would be automatically translated into practice, but it doesn’t mean that other possibly more affordable forms of this type of medication might be developed," Professor Farrell said. One aspect of the research not published in the JAMA paper, was that when the researchers looked at the data 12 weeks after participants stopped taking nabiximols, most of the changes the participants made had persisted.