Cannabis species and subspecies have been used medicinally for over 5,000 years, though cultivation may reach as far back as 10,000 years.1 In the United States, the regulation of cannabis as a Schedule I drug has hampered the study of cannabis and its medicinal uses. Since California became the first state to legalize medical marijuana in 1996, almost 30 states and the District of Columbia have followed, and more states are expected to legalize medical marijuana. As a result, there have been recent reviews and studies related to medicinal marijuana. The inquiry made by older and more recent studies is whether cannabis is effective to treat nausea and vomiting due to chemotherapy, stimulating the appetite of patients with human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS), chronic pain, seizures, and other conditions or diseases. The results are mixed but in certain instances there is encouraging evidence that cannabis may provide relief for certain conditions. A brief overview of the history of cannabis species and subspecies is covered in the following first sections1 prior to a more in depth discussion of the botanical chemistry and physiological effects of cannabis in controlled trials and medical studies that focused on its effects related to various human diseases and conditions.
A Brief History Of Hemp
Hemp, a non-psychoactive species of Cannabis sativa, has provided the oldest known fabric, dating to 8000 BCE (before common era). In the 9th BCE, the Chinese emperor was offered a tribute of hemp-cloth by a tribe of female warriors. The cloth was described as shining and radiant, infecting men with its sweet-smelling aroma. Burnt remnants of Cannabis have been found in burial mounds in Siberia and have been dated to 3000 BCE. Imprints of hemp rope are found on pottery in ancient Chinese burial chambers dating to about 10,000 BCE. The hemp nut has been used for bread and cereals, the oil has been used for fuel, lubricants and moisturizers, ink, food and paint. Hemp stalk has been used for its fiber in making fabrics, paper, rope, netting, footwear, biofuel and building materials.
In colonial America, hemp was George Washington’s and Thomas Jefferson’s main cash crop. The British navy was one of the primary users of hemp, using hemp oil, rope, paper, fiber and cloth for riggings, pennants, sails, oakum, maps, logs, and for any books that sailors brought for their long sea voyages. The term for a British sailor Jack Tar came from the fact that the hemp ropes had to be heavily tarred to keep from rotting. Benjamin Franklin started the first paper mill in America; it produced hemp paper and is believed to have provided the hemp paper on which the Declaration of Independence was written.
Hemp is also used as food. Hemp seeds, often referred to as hemp hearts are highly nutritious. Hemp hearts are a complete protein source and contain significant amounts of both the omega-6 essential fatty acid (EFA), linoleic acid, and the omega-3 EFA, linolenic acid in ratios that range from 2 to 3:1, considered the healthiest ratio. In addition, hemp hearts contain gamma-linolenic acid (GLA 18:3 omega-6 and stearidonic acid (SDA 18:4 omega-3). Hemp seeds are also high in calcium, magnesium, potassium, iron, manganese and zinc. Hemp seeds and roots, while not primarily medicinal, have been used to treat topical inflammation, incontinence and venereal disease.
For a variety of reasons, hemp has often been confused with the psychoactive species of cannabis. In the early 1900s, there was a significant influx of Mexicans into, primarily, the American Southwest. While many Americans were familiar with cannabis, these Mexican migrants referred to cannabis as marijuana. Earlier immigrations had seen the demonization of immigrants and the efforts to restrict immigration had in previous years taken the form of outlawing substances known to be popular in these immigrant groups. For example, opium was restricted to control Chinese immigration and groups associated with the Prohibition and were often associated with various anti-immigrant groups and anti-African-American groups. While the situation is more complicated, historians point to a backlash directed at people of color in many restrictive laws of the era. Physicians and society in general was becoming aware of the addictive properties of opium and morphine. Mexicans, African-Americans, other minority groups or criminals were portrayed as “dope fiends” and laws were passed in part to prevent morphine/opium addicts from using home-grown marijuana as a substitute, but also in an attempt to control crime.
By the end of the 19th century, it is estimated that between 2-5% of the population in the U.S., was addicted, often without knowing it, to opium and morphine derivatives. Popular products containing opium (up to 0.5g/oz.) were sold as treatments for colic, pain, anxiety, sleep disturbances, migraines and a host of other conditions. Overstressed mothers used popular products like Godfrey’s Cordial, Mrs. Winslow’s Soothing Syrup and Street’s Infants’ Quietness to help soothe their colicky baby. Godfrey’s Cordial contained 1 gram of opium in every 2 ounces. There were other popular products such as Dr. Fenner's Golden Relief, the People's Healing Liniment for Man or Beast and various other products which contained opium or morphine. The Sears and Roebuck catalog sold a syringe with cocaine for $1.50. At the time, Coca Cola contained approximately 5 ounces of coca leaves for every gallon of syrup. Marijuana was also getting similar attention. The growing understanding of opiate addiction may have met the economic and social anxieties of the era to form a backlash against all cannabis products, whether used as a drug or medicine or for fabric-making and food.
In 1937, the Marijuana Tax Act strictly regulated the cultivation and sale of all cannabis varieties, including hemp. This act made the nonmedical use of marijuana illegal, though its primary purpose was taxation. (The birdseed industry lobbied to be exempt as they argued that hemp seeds gave birds a highly prized shiny gloss). All of this occurred just after prohibition (1920-1933) and the argument has been made that a new source of revenue was needed. Hemp production and cultivation farming in the U.S. was greatly reduced until World War II. In World War II, the film “Hemp for Victory” was made to stress the need for hemp to make war materials. Hemp is used as a “mop crop;” it is used to clean up sewage spills, oil spills and nuclear waste. Hemp is also an attractive rotation crop for many farmers, requires no extra fertilization or pesticides and is heat- and drought-resistant.