A 2012 review found that the THC content in marijuana had increased worldwide from 1970 to 2009. It is unclear, however, whether the increase in THC content has caused people to consume more THC or if users adjust based on the potency of the cannabis. It is likely that the higher THC content allows people to ingest less tar. At the same time, CBD levels in seized samples have lowered, in part because of the desire to produce higher THC levels and because more illegal growers cultivate indoors using artificial lights. This helps avoid detection but reduces the CBD production of the plant.
Marijuana and hemp both come from the same species of plant, Cannabis sativa. Once it was discovered the plant’s flowers can can have psychoactive effects, cultivators began growing separate strains of the plant – one normal variety, and one whose flowers contained higher levels of the cannabinoid tetrahydrocannabinol (THC), leading to tighter regulation.
In recent decades, the neurobiology of cannabinoids has been analyzed.[12-15] The first cannabinoid receptor, CB1, was identified in the brain in 1988. A second cannabinoid receptor, CB2, was identified in 1993. The highest expression of CB2 receptors is located on B lymphocytes and natural killer cells, suggesting a possible role in immunity. Endogenous cannabinoids (endocannabinoids) have been identified and appear to have a role in pain modulation, control of movement, feeding behavior, mood, bone growth, inflammation, neuroprotection, and memory.
Hemp paper is useful for specialty applications such as currency and cigarette papers where strength is needed. The bast fiber is of greatest interest to the pulp and paper industry because of its superior strength properties compared to wood. However, the short, bulky fibers found in the inner part of the plant (hurds) can also be used to make cheaper grades of paper, apparently without greatly affecting quality of the printing surface. Hemp is not competitive for newsprint, books, writing papers, and general paper (grocery bags, coffee cups, napkins), although there is a specialty or novelty market for those specifically wishing to support the hemp industry by purchasing hemp writing or printing paper despite the premium price (Fig. 17).
Hashish (also spelled hasheesh, hashisha, or simply hash) is a concentrated resin cake or ball produced from pressed kief, the detached trichomes and fine material that falls off cannabis flowers and leaves. or from scraping the resin from the surface of the plants and rolling it into balls. It varies in color from black to golden brown depending upon purity and variety of cultivar it was obtained from. It can be consumed orally or smoked, and is also vaporised, or 'vaped'. The term "rosin hash" refers to a high quality solventless product obtained through heat and pressure.
Some jurisdictions use free voluntary treatment programs and/or mandatory treatment programs for frequent known users. Simple possession can carry long prison terms in some countries, particularly in East Asia, where the sale of cannabis may lead to a sentence of life in prison or even execution. Political parties, non-profit organizations, and causes based on the legalization of medical cannabis and/or legalizing the plant entirely (with some restrictions) have emerged in such countries as China and Thailand.
Since Cannabis smoke contains many of the same components as tobacco smoke, there are valid concerns about the adverse pulmonary effects of inhaled Cannabis. A longitudinal study in a noncancer population evaluated repeated measurements of pulmonary function over 20 years in 5,115 men and women whose smoking histories were known. While tobacco exposure was associated with decreased pulmonary function, the investigators concluded that occasional and low-cumulative Cannabis use was not associated with adverse effects on pulmonary function (forced expiratory volume in the first second of expiration [FEV1] and forced vital capacity [FVC]).
The plant is also known as hemp, although this term is often used to refer only to varieties of Cannabis cultivated for non-drug use. Cannabis has long been used for hemp fibre, for hemp oils, for medicinal purposes, and as a recreational drug. Industrial hemp products are made from cannabis plants selected to produce an abundance of fiber. To satisfy the UN Narcotics Convention, some cannabis strains have been bred to produce minimal levels of tetrahydrocannabinol (THC), the principal psychoactive constituent. Some strains have been selectively bred to produce a maximum of THC (a cannabinoid), the strength of which is enhanced by curing the flowers. Various compounds, including hashish and hash oil, are extracted from the plant.
Marijuana or marihuana (herbal cannabis), consists of the dried flowers and subtending leaves and stems of the female Cannabis plant. This is the most widely consumed form, containing 3% to 20% THC, with reports of up-to 33% THC. This is the stock material from which all other preparations are derived. Although herbal cannabis and industrial hemp derive from the same species and contain the psychoactive component (THC), they are distinct strains with unique biochemical compositions and uses. Hemp has lower concentrations of THC and higher concentrations of CBD, which decreases the psychoactive effects
Australia's National Cannabis Prevention and Information Centre (NCPIC) states that the buds (flowers) of the female cannabis plant contain the highest concentration of THC, followed by the leaves. The stalks and seeds have "much lower THC levels". The UN states that leaves can contain ten times less THC than the buds, and the stalks one hundred times less THC.
There are also other difficulties in researching the effects of cannabis. Many people who smoke cannabis also smoke tobacco. This causes confounding factors, where questions arise as to whether the tobacco, the cannabis, or both that have caused a cancer. Another difficulty researchers have is in recruiting people who smoke cannabis into studies. Because cannabis is an illegal drug in many countries, people may be reluctant to take part in research, and if they do agree to take part, they may not say how much cannabis they actually smoke.
Some manufacturers ship CBD products nationally, an illegal action which the FDA has not enforced in 2018, with CBD remaining as the subject of an FDA investigational new drug evaluation and is not considered legal as a dietary supplement or food ingredient as of November 2018. CBD is openly sold in head shops and health food stores in some states where such sales have not been explicitly legalized.
In December 2013, Uruguay became the first country to legalize growing, sale and use of cannabis. After a long delay in implementing the retail component of the law, in 2017 sixteen pharmacies were authorized to sell cannabis commercially. On June 19, 2018, the Canadian Senate passed a bill and the Prime Minister announced the effective legalization date as October 17, 2018. Canada is the second nation to legalize the drug.
Those warning letters aside, there’s not a lot of federal oversight right now over the claims being made or the products that are being sold. Cohen warned against buying CBD products online, because “there’s a lot of scams out there.” Yet his clinic sells CBD, and he admits, “I say ‘Don’t buy online,’ but ours is worth doing, because we know what we’re doing. We ship all over.”
After revisions to cannabis scheduling in the UK, the government moved cannabis back from a class C to a class B drug. A purported reason was the appearance of high potency cannabis. They believe skunk accounts for between 70 and 80% of samples seized by police (despite the fact that skunk can sometimes be incorrectly mistaken for all types of herbal cannabis). Extracts such as hashish and hash oil typically contain more THC than high potency cannabis flowers.
Only a handful of countries have legalized recreational marijuana. Uruguay was one of the first, in 2013. The Netherlands is perhaps the country most known for legal marijuana, yet the drug is illegal there. Spain has given its citizens the rights to grow and consume cannabis privately. Peru also allows citizens to possess marijuana as long as it is for personal, private use. As in Costa Rica, where people can have a “small amount,” without legal trouble.
In the UK, the Department for Environment, Food and Rural Affairs treats hemp as a purely non-food crop, but with proper licensing and proof of less than 0.2% THC concentration, hemp seeds can be imported for sowing or for sale as a food or food ingredient. In the U.S., imported hemp can be used legally in food products and, as of 2000, was typically sold in health food stores or through mail order.