was introduced into Western medicine in the 1840s by W.B. O’Shaughnessy, and was a topic of great interest at the first American conference on its clinical use, held by the Ohio State Medical Society in 1860. Physicians reported success in using cannabis to treat chronic cough, gonorrhea, pain, and a variety of other conditions.2
By the 1930s, at least two American companies were selling standardized extracts of cannabis for use as an analgesic, antispasmodic, and sedative.3 Shortly after these became available, synthetic drugs such as aspirin and barbiturates began to replace the use of cannabis extracts. During this time, the recreational use of marijuana gained in popularity in the United States, bringing with it claims that it caused crime, mental illness, and even death.
Against the advice of the American Medical Association, the US Congress passed the Marijuana Tax Act of 1937, imposing tough restrictions on marijuana sales and prescription, ultimately driving most pharmaceutical companies to cease production of their cannabis-based drugs.
In 1942, cannabis was removed from the United States Pharmacopoeia on the grounds that it was a harmful and addictive drug.4 Over the next 3 decades, through passage of legislation by the US Congress, cannabis deteriorated from an accepted and widely used herbal remedy to classification as a Schedule I drug, distinguished as having no accepted medical use and in the company of substances like heroin, LSD, and mescaline, among others.
In spite of this, the US FDA approved a synthetic cannabis component, delta-9- tetrahydrocannabinol (THC), (dronabinol; Marinol®) for the treatment of chemotherapy-associated nausea and vomiting in 1986; expanded indications for the treatment of anorexia associated with HIV followed in 1992. In both cases, clinical trials demonstrated safety and efficacy as required for licensure in the US.5 Twenty-three states and the District of Columbia have now enacted laws to permit the medical use of cannabis. Research into the mechanism of its action and benefits is currently revolutionizing our thinking on this centuries-old remedy.