Supply and control reduction are controversial interventions, lacking evidence of more than marginal effectiveness, and have distracted attention from the possibility of effective harm reduction for cannabis.

Although attempts to reduce demand and supply are valid, there are inevitable limitations of these approaches. Harm reduction approaches to the control of alcohol-related problems should be considered as complementing demand and supply reduction.

Harm reduction is often accepted as a valid public health framework for approaching population health problems but rarely considered to have application to the clinical management of people with alcohol and drug-related problems.

Attempts to reduce drug use sometimes decrease consumption and also sometimes reduce harm, especially in the case of legal drugs. However, attempts to reduce consumption of illegal drugs often not only fail to reduce demand or supply but also inadvertently increase the adverse consequences.

The term ‘harm reduction’ was originally used in the early 1980s to refer to policies and programmes directed primarily at reducing the adverse health consequences of mood altering drugs. This interpretation is still common. However, these days, the term ‘harm reduction’ is also sometimes used to mean all measures that might reduce drug-related harms.