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Published: 15 November 2011

Adverse health effects of cannabis use

The individual health risk related to cannabis use is generally accepted to be lower than those associated with drugs such as heroin or cocaine. However, due to the high prevalence of cannabis use, the impact of the drug on public health may be significant.

A range of acute and chronic health problems associated with cannabis use have been identified. Acute adverse effects include anxiety, panic reaction and psychotic symptoms, which may be more commonly reported by first-time users. Cannabis use can also increase the risk of being involved in a traffic accident.

Chronic effects linked to cannabis use have been documented, including dependence and a number of respiratory diseases. The impact of cannabis use on cognitive performance remains unclear. Regular cannabis use in adolescence might adversely affect mental health in young adults, and there is evidence of increased risks of psychotic symptoms and disorders with increasing frequency of use (EMCDDA, 2008a, 2008b; Hall and Degenhardt, 2009; Moore et al., 2007).

EMCDDA (2008a), A cannabis reader: global issues and local experiences, Monograph, Publications Office of the European Union, Luxembourg.

EMCDDA (2008b), Drug use, impaired driving and traffic accidents, Insight, Publications Office of the European Union, Luxembourg.

Hall, W. and Degenhardt, L. (2009), 'Adverse health effects of non-medical cannabis use', Lancet 374, pp. 1 383-91.

Moore, T.H., Zammit, S., Lingford-Hughes, A., Barnes, T.R., Jones, P.B. et al. (2007), 'Cannabis use and risk of psychotic or affective mental health outcomes: a systematic review', Lancet 370, pp. 319-28.

About the EMCDDA

The European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) is the reference point on drugs and drug addiction information in Europe. Inaugurated in Lisbon in 1995, it is one of the EU's decentralised agencies. Read more >>

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Page last updated: Friday, 28 October 2011