Cannabis plants produce a unique family of terpeno-phenolic compounds called cannabinoids, some of which produce the "high" which may be experienced from consuming marijuana. There are 483 identifiable chemical constituents known to exist in the cannabis plant, and at least 85 different cannabinoids have been isolated from the plant. The two cannabinoids usually produced in greatest abundance are cannabidiol (CBD) and/or Δ9-tetrahydrocannabinol (THC), but only THC is psychoactive. Since the early 1970s, Cannabis plants have been categorized by their chemical phenotype or "chemotype", based on the overall amount of THC produced, and on the ratio of THC to CBD. Although overall cannabinoid production is influenced by environmental factors, the THC/CBD ratio is genetically determined and remains fixed throughout the life of a plant. Non-drug plants produce relatively low levels of THC and high levels of CBD, while drug plants produce high levels of THC and low levels of CBD. When plants of these two chemotypes cross-pollinate, the plants in the first filial (F1) generation have an intermediate chemotype and produce intermedite amounts of CBD and THC. Female plants of this chemotype may produce enough THC to be utilized for drug production.
In addition to acting on the brain, CBD influences many body processes. That’s due to the endocannabinoid system (ECS), which was discovered in the 1990s, after scientists started investigating why pot produces a high. Although much less well-known than the cardiovascular, reproductive, and respiratory systems, the ECS is critical. “The ECS helps us eat, sleep, relax, forget what we don’t need to remember, and protect our bodies from harm,” Marcu says. There are more ECS receptors in the brain than there are for opioids or serotonin, plus others in the intestines, liver, pancreas, ovaries, bone cells, and elsewhere.
^ Jump up to: a b Schreiner AM, Dunn ME (October 2012). "Residual effects of cannabis use on neurocognitive performance after prolonged abstinence: a meta-analysis". Experimental and Clinical Psychopharmacology. 20 (5): 420–429. doi:10.1037/a0029117. PMID 22731735. Therefore, results indicate evidence for small neurocognitive effects that persist after the period of acute intoxication...As hypothesized, the meta-analysis conducted on studies eval- uating users after at least 25 days of abstention found no residual effects on cognitive performance...These results fail to support the idea that heavy cannabis use may result in long-term, persistent effects on neuropsychological functioning.
One systematic review studied 30 randomized comparisons of delta-9-THC preparations with placebo or other antiemetics from which data on efficacy and harm were available. Oral nabilone, oral dronabinol, and intramuscular levonantradol (a synthetic analog of dronabinol) were tested. Inhaled Cannabis trials were not included. Among all 1,366 patients included in the review, cannabinoids were found to be more effective than the conventional antiemetics prochlorperazine, metoclopramide, chlorpromazine, thiethylperazine, haloperidol, domperidone, and alizapride. Cannabinoids, however, were not more effective for patients receiving very low or very high emetogenic chemotherapy. Side effects included a feeling of being high, euphoria, sedation or drowsiness, dizziness, dysphoria or depression, hallucinations, paranoia, and hypotension.
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]).
Cooper recently got funding from the National Institutes of Health for a study looking at cannabinoids — including CBD in isolation — as a substitute for opioids, and numerous other clinical trials of CBD are underway. It will be several years before results are available, but these studies should help clarify both what benefits the substance may provide and any side effects it may come with. Most of the adverse effects so far associated with cannabis, such as impairments in short-term memory, coordination and judgment,2 come from products that contain THC as well as CBD, Cooper said, but we need to do more studies to find out for sure whether CBD has fewer risks. Studies are also needed to identify the best way to administer and dose CBD. “I get emails from people asking me what dose of CBD to use, and the truth is, we really don’t know,” Cooper said.
Whether the drug and non-drug, cultivated and wild types of Cannabis constitute a single, highly variable species, or the genus is polytypic with more than one species, has been a subject of debate for well over two centuries. This is a contentious issue because there is no universally accepted definition of a species. One widely applied criterion for species recognition is that species are "groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups." Populations that are physiologically capable of interbreeding, but morphologically or genetically divergent and isolated by geography or ecology, are sometimes considered to be separate species. Physiological barriers to reproduction are not known to occur within Cannabis, and plants from widely divergent sources are interfertile. However, physical barriers to gene exchange (such as the Himalayan mountain range) might have enabled Cannabis gene pools to diverge before the onset of human intervention, resulting in speciation. It remains controversial whether sufficient morphological and genetic divergence occurs within the genus as a result of geographical or ecological isolation to justify recognition of more than one species.
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.
Cannabis was also known to the ancient Assyrians, who discovered its psychoactive properties through the Iranians. Using it in some religious ceremonies, they called it qunubu (meaning "way to produce smoke"), a probable origin of the modern word "cannabis". The Iranians also introduced cannabis to the Scythians, Thracians and Dacians, whose shamans (the kapnobatai—"those who walk on smoke/clouds") burned cannabis flowers to induce trance.
Hemp fiber has been used extensively throughout history, with production climaxing soon after being introduced to the New World. For centuries, items ranging from rope, to fabrics, to industrial materials were made from hemp fiber. Hemp was also commonly used to make sail canvas. The word "canvas" is derived from the word cannabis. Pure hemp has a texture similar to linen. Because of its versatility for use in a variety of products, today hemp is used in a number of consumer goods, including clothing, shoes, accessories, dog collars, and home wares.
Our award-winning support staff, experienced cultivators, and network of healthcare practitioners are here to help remove barriers to medical cannabis. We’re honoured to be part of a movement that’s helping Canadians across the country access their medicine; and as we grow we will continue to provide patients with reliable access to safe, consistent, and effective medical cannabis.