Fig. 25. The “hemp house” under construction on the Oglala Lakota Nation (Pine Ridge Reservation), South Dakota. Foundation blocks for the house are made with hemp fiber as a binder in cement. Stucco is also of hemp. Shingles are 60% hemp in a synthetic polymer. Hemp insulation is used throughout. (Courtesy of Oglala Sioux Tribe, Slim Butte Land Use Association, and S. Sauser.)
Exactly how and when hemp originated in the New World is still highly debated. Though long thought to be introduced to the Americas by Christopher Columbus, hemp has been discovered in Native American civilizations that predate Columbus’ arrival. William Henry Holmes’ “Prehistoric Textile Art of Eastern United States” report from 1896 notes hemp from Native American tribes of the Great Lakes and Mississippi Valley. Hemp products from pre-Columbian native civilizations were also found in Virginia. Vikings, who depended on hemp for making rope and sails, may also have brought hemp seeds with them when they attempted to colonize the New World.
Molecular analytical techniques developed in the late 20th century are being applied to questions of taxonomic classification. This has resulted in many reclassifications based on evolutionary systematics. Several studies of Random Amplified Polymorphic DNA (RAPD) and other types of genetic markers have been conducted on drug and fiber strains of Cannabis, primarily for plant breeding and forensic purposes. Dutch Cannabis researcher E.P.M. de Meijer and coworkers described some of their RAPD studies as showing an "extremely high" degree of genetic polymorphism between and within populations, suggesting a high degree of potential variation for selection, even in heavily selected hemp cultivars. They also commented that these analyses confirm the continuity of the Cannabis gene pool throughout the studied accessions, and provide further confirmation that the genus consists of a single species, although theirs was not a systematic study per se.
Genetics, or inherited traits from parents, also play a role in determining the health status of individuals and populations. This can encompass both the predisposition to certain diseases and health conditions, as well as the habits and behaviors individuals develop through the lifestyle of their families. For example, genetics may play a role in the manner in which people cope with stress, either mental, emotional or physical. For example, obesity is a significant problem in the United States that contributes to bad mental health and causes stress in the lives of great numbers of people. (One difficulty is the issue raised by the debate over the relative strengths of genetics and other factors; interactions between genetics and environment may be of particular importance.)
Way back when, an angry and lobby-influenced Congress passed the Marihuana Tax Act of 1937, which effectively outlawed the possession of cannabis—including hemp—after hundreds of years of growth and use from the time of British colonization onward. While that law was repealed in the late 1960s, cannabis was quickly included as a Schedule 1 drug (the most “dangerous” class of drugs including heroin) in the Controlled Substances Act, a designation which continues to this day.
In 2015, almost half of the people in the United States had tried marijuana, 12% had used it in the past year, and 7.3% had used it in the past month. In 2014, daily marijuana use amongst US college students had reached its highest level since records began in 1980, rising from 3.5% in 2007 to 5.9% in 2014 and had surpassed daily cigarette use.
Selective breeding of cannabis plants has expanded and diversified as commercial and therapeutic markets develop. Some growers in the U.S. succeeded in lowering the proportion of CBD-to-THC to accommodate customers who preferred varietals that were more mind-altering due to the higher THC and lower CBD content. Hemp is classified as any part of the cannabis plant containing (depending on the jurisdiction) no more than 0.2% to 1.0% THC in dry weight form (not liquid or extracted form).[unreliable source?]
In a SAFEX study of Phase III double-blind RCT in 160 subjects with various symptoms of MS (Wade et al 2004), 137 patients elected to continue on Sativex after the initial study (Wade et al 2006). Rapid declines were noted in the first twelve weeks in pain VAS (N = 47) with slower sustained improvements for more than one year. During that time, there was no escalation of dose indicating an absence of tolerance to the preparation. Similarly, no withdrawal effects were noted in a subset of patients who voluntarily stopped the medicine abruptly. Upon resumption, benefits resumed at the prior established dosages.