The first reports of using marijuana medically date from 2737 B.C. when it was mentioned in ancient medical texts in China. Ancient texts from India, Africa, Greece and elsewhere refer to its medicinal use. Modern western medicine first became aware of medical marijuana when an Irish doctor, William O'Shaughnessy, wrote about it after returning from India in 1842. The United States Pharmacopeia (USP) is the official register of legitimate medicinal products for the US; marijuana was added in 1851. It was recommended in those days for pain relief, muscle relaxation, appetite stimulation, and sedation. Concerns about its recreational hallucinogenic use led to it being criminalized in the US in 1937 and removed from the USP in 1942. In 1970 it was listed as a Schedule 1 drug, meaning it has no accepted medical use and many dangers.
In spite of this legal classification, marijuana remained in use within some alternative medicine circles, as well as becoming the most widely used illegal drug in the US. Such recreational use continues to increase among adolescents and young adults. Controversy over its legal status came to greater public attention when California passed Proposition 215 in 1996. Now 20 states and the District of Columbia have voted to legalize marijuana for medicinal purposes. Such an approach raises concerns about whether any medical therapy should be approved by popular vote rather than expert review as normally carried out by the Food & Drug Administration (FDA). Two states have legalized its use for recreational purposes, and a recent poll found that three-quarters believe marijuana use will be legal nationwide soon.
Before examining the details of this controversy, clarification is needed on a number of different terms used in this debate, particularly "medical marijuana." This paper is concerned primarily with the use of plant material from Cannabis sativa either to get high or to treat various conditions, particularly chronic pain, weight loss, and glaucoma. The plant is most usually smoked, although it is also consumed in other ways, being mixed into various foods like brownies and cookies. The term "medical marijuana" will be used here for this specific use. Marijuana is used in the same ways (primarily smoked) for recreational purposes to get high, relax, and trigger other perceptual changes. Together, these are called marijuana's psychoactive effects and are viewed as its benefits by recreational users but (usually) its adverse effects by medicinal users. Whenever marijuana is used without being prefaced by 'medical,' its recreational use will be intended.