Medical cannabis (or medical marijuana) refers to the use of cannabis and its constituent cannabinoids, such as tetrahydrocannabinol (THC) and cannabidiol (CBD), as medical therapy to treat disease or alleviate symptoms. The Cannabis plant has a history of medicinal use dating back thousands of years across many cultures. Its usage in modern times is controversial, and in recent years the American Medical Association, the MMA, the American Society of Addiction Medicine, and other medical organizations have issued statements opposing its usage for medicinal purposes. The American Academy of Pediatrics states that while cannabinoids may have potential as therapy for a number of medical conditions, they do not recommend their use until more research can be done. They call for moving cannabis from DEA Schedule 1 to DEA Schedule 2 to facilitate this research.
Cannabis has been used to reduce nausea and vomiting in chemotherapy and people with HIV/AIDS, and to treat pain and muscle spasticity; its use for other medical applications has been studied, but there is insufficient data for conclusions about safety and efficacy. Short-term use increases minor adverse effects, but does not appear to increase major adverse effects. Long-term effects of cannabis are not clear, and there are safety concerns including memory and cognition problems, risk for dependence and the risk of children taking it by accident.
Medical cannabis can be administered using a variety of methods, including vaporizing or smoking dried buds, eating extracts, taking capsules or using oral sprays. Synthetic cannabinoids are available as prescription drugs in some countries; examples include: dronabinol (available in the United States (US) and Canada) and nabilone (available in Canada, Mexico, the United Kingdom (UK), and the US). Recreational use of cannabis is illegal in most parts of the world, but the medical use of cannabis is legal in certain countries, including Austria, Canada, Czech Republic, Finland, Germany, Israel, Italy, the Netherlands, Portugal and Spain. In the US, federal law outlaws all cannabis use, while 20 states and the District of Columbia no longer prosecute individuals merely for the possession or sale of marijuana, as long as the individuals are in compliance with the state's marijuana sale regulations. However, an appeals court ruled in January 2014 that a 2007 Ninth Circuitruling remains binding in relation to the ongoing illegality, in federal legislative terms, of Californian cannabis dispensaries, reaffirming the impact of the federal Controlled Substances Act.