The term "medical cannabis" describes the use of the cannabis or marijuana plant, or derivatives of the plant, as a type of medical therapy. When eaten or smoked, the psychoactive substances in the plant can help alleviate symptoms such as pain, nausea and muscle spasms. Medical cannabis can be referred to in several other ways, including medicinal cannabis, medicinal marijuana, medical marijuana, medical pot or medical weed.
Leaves, flowers, and resin from Cannabis sativa are used in many countries as a recreational drug. Many cultures, both ancient and modern, have used the drug in spiritual rites and practices. Currently, the cultivation, sale and use of Cannabis sativa is illegal in many places, but other places have legalized certain aspects of cannabis usage.
Tetrahydrocannabinol (THC), the psychoactive substance that produces the "high" gained from smoking or eating the Cannabis sativa plant, also can help alleviate certain medical symptoms. Because of this, the use of medical cannabis has been legalized in some countries. In Austria, Canada, Germany, Spain and some parts of the United States, use of medicinal cannabis, or certain cannabis derivatives, is legal.
In countries or states where use of medicinal cannabis is legal, people who wish to use the substance for medical purposes must first obtain permission to do so. Permission typically is granted by an individual’s doctor. Depending on where the individual lives, he or she might be supplied with an identification card or similar document indicating that they are legally allowed to use cannabis for medical purposes.
Medical cannabis has been shown, in many scientific publications, to have positive effects on symptoms of a wide range of diseases and medical conditions. TCH can reduce stress, alleviate pain, reduce nausea, relax the muscles and stimulate the appetite. These properties have produced positive effects in treating symptoms of premenstrual syndrome, glaucoma, asthma, inflammatory bowel disease, migraines, multiple sclerosis, arthritis, epilepsy, depression, hypertension and Parkinson’s disease. In addition, concentrated, targeted doses of THC have, in laboratory testing, been shown to prevent the growth and spread of certain types of tumors, including breast and lung tumors.
One of the simplest but most effective uses of medical cannabis is in treating the loss of appetite associated with HIV/AIDS and chemotherapy cancer treatment. TCH stimulates the appetite even in small doses, by acting on the hypothalamus in the brain. In addition to many other roles, the hypothalamus is the body’s hunger control center, where hormones are manufactured and released in response to food-related stimuli. TCH not only stimulates the appetite, it also makes food more palatable. This makes medicinal cannabis a useful treatment for people undergoing chemotherapy as a cancer treatment, because chemotherapy tends to cause extreme nausea and loss of appetite.
Opponents of the use of medical marijuana, particularly physicians who oppose the practice, do so on the grounds that long-term use of the substance can cause short-term memory difficulties and other cognitive impairments. In addition, people who are vulnerable to psychosis might be made more so by the use of cannabis. The substance also is psychologically and physically addictive.
Advocates of the practice believe that the benefits far outweigh the potential negative effects. In contrast to studies highlighting the negative effects of cannabis use, other studies indicate that cannabis use does not cause permanent damage to the brain. Studies also suggest that the substance is no more addictive than caffeine.