Assessment and management of cannabis use disorders in primary care.

Cite this as: BMJ 2010;340:c1571 doi: 10.1136/bmj.c1571 About a third of adults in the UK have tried cannabis, and 2.5 million people, mostly 16-29 year olds, have used it in the past year. Although most people who smoke cannabis will develop neither severe mental health problems nor dependence, regular use of cannabis may be associated with a range of health, emotional, behavioural, social, and legal problems, particularly in young, pregnant, and severely mentally ill people. 3 The past decade has seen a shift in available cannabis preparations from resinous “hash” to intensively grown high potency herbal preparations, often referred to as skunk, which now dominates the UK market. Compared with traditional cannabis preparations, skunk tends to have higher levels of tetrahydrocannabinol, the main psychoactive constituent of cannabis, and lower levels of the anxiolytic cannabinoid cannabidiol. In January 2009 cannabis was returned to its original class B classification (from class C) under the UK Misuse of Drugs Act. Despite high levels of use, only 6% of those seeking treatment for substance misuse in England cite cannabis as their major drug of concern, and most of those with cannabis use disorders do not have cannabis use as their presenting complaint (box 1). Low levels of treatment seeking may reflect a lack of awareness of the associated harms of cannabis. This review highlights the adverse health outcomes associated with cannabis and outlines optimal approaches to assessing and managing cannabis use in primary care.