Marijuana.

Marijuana remains a complex, poorly understood drug with many effects. Although its acute psychological effects are well described, data linking cannabis use to chronic psychiatric or social problems and decreased driving or workplace safety are much less clear. Current laboratory procedures have not yet been shown useful to demonstrate acute intoxication, so they remain screening instruments for those interested in detecting cannabis use for other reasons. Although both acute and chronic effects of marijuana use have been described, they appear to be less than other commonly abused substances, including tobacco and alcohol. The rare acute complications that present to the Emergency Department can be managed with conservative measures.