 Drug decriminalisation, such as allowing the possession of small amounts of cannabis and possibly its cultivation for personal use, would alleviate these harms.Where decriminalisation has been implemented, such as in several states in Australia and United States, as well as in Portugal and the Netherlands no, or only very small adverse effects have been shown on population cannabis usage rate.The lack of evidence of increased use indicates that such a policy shift does not have adverse effects on cannabis-related harm while, at the same time, decreasing enforcement costs.