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,[48] and at least 85 different cannabinoids have been isolated from the plant.[49] The two cannabinoids usually produced in greatest abundance are cannabidiol (CBD) and/or Δ9-tetrahydrocannabinol (THC), but only THC is psychoactive.[50] 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.[51] 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.[36] 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.[51][52]

State policymakers have taken action to address various policy issues — the definition of hemp, licensure of growers, regulation and certification of seeds, state-wide commissions and legal protection of growers. At least 41 states have passed legislation related to industrial hemp, such as defining hemp and removing barriers, and at least 39 states have allowed for hemp cultivation and production programs. Some states establishing these programs require a change in federal laws or a waiver from the DEA prior to implementation.

Cannabis use generally makes psychotic symptoms worse and lowers the person’s chances of recovery from a psychotic episode. People with a psychotic illness who use drugs experience more delusions, hallucinations and other symptoms. They have a higher rate of hospitalisation for psychosis, and treatment is generally less effective for them. People with a psychotic illness should not use cannabis.
Both in Canada and the US, the most critical problem to be addressed for commercial exploitation of C. sativa is the possible unauthorized drug use of the plant. Indeed, the reason hemp cultivation was made illegal in North America was concern that the hemp crop was a drug menace. The drug potential is, for practical purposes, measured by the presence of THC. THC is the world’s most popular illicit chemical, and indeed the fourth most popular recreational drug, after caffeine, alcohol, and nicotine. “Industrial hemp” is a phrase that has become common to designate hemp used for commercial non-intoxicant purposes. Small and Cronquist (1976) split C. sativa into two subspecies: C. sativa subsp. sativa, with less than 0.3% (dry weight) of THC in the upper (reproductive) part of the plant, and C. sativa subsp. indica (Lam.) E. Small & Cronq. with more than 0.3% THC. This classification has since been adopted in the European Community, Canada, and parts of Australia as a dividing line between cultivars that can be legally cultivated under license and forms that are considered to have too high a drug potential. For a period, 0.3% was also the allowable THC content limit for cultivation of hemp in the Soviet Union. In the US, Drug Enforcement Agency guidelines issued Dec. 7, 1999 expressly allowed products with a THC content of less than 0.3% to enter the US without a license; but subsequently permissible levels have been a source of continuing contention. Marijuana in the illicit market typically has a THC content of 5% to 10% (levels as high as 25% have been reported), and as a point of interest, a current Canadian government experimental medicinal marijuana production contract calls for the production of 6% marijuana. As noted above, a level of about 1% THC is considered the threshold for marijuana to have intoxicating potential, so the 0.3% level is conservative, and some countries (e.g. parts of Australia, Switzerland) have permitted the cultivation of cultivars with higher levels. It should be appreciated that there is considerable variation in THC content in different parts of the plant. THC content increases in the following order: achenes (excluding bracts), roots, large stems, smaller stems, older and larger leaves, younger and smaller leaves, flowers, perigonal bracts covering both the female flowers and fruits. It is well known in the illicit trade how to screen off the more potent fractions of the plant in order to increase THC levels in resultant drug products. Nevertheless, a level of 0.3% THC in the flowering parts of the plant is reflective of material that is too low in intoxicant potential to actually be used practically for illicit production of marijuana or other types of cannabis drugs. Below, the problem of permissible levels of THC in food products made from hempseed is discussed.
A CNN program that featured Charlotte's Web cannabis in 2013 brought increased attention to the use of CBD in the treatment of seizure disorders.[68][69] Since then, 16 states have passed laws to allow the use of CBD products with a doctor's recommendation (instead of a prescription) for treatment of certain medical conditions.[70] This is in addition to the 30 states that have passed comprehensive medical cannabis laws, which allow for the use of cannabis products with no restrictions on THC content.[70] Of these 30 states, eight have legalized the use and sale of cannabis products without requirement for a doctor's recommendation.[70]
We also rated the product based on the type of CBD they used: isolate, full-spectrum decarb, broad-spectrum, or distillate. There’s a lot of debate around what is actually best, but our first decision was to give points to CBD oil that contains a range of cannabinoids. While there are certainly people with good reasons for choosing an isolate, there’s a lot of good evidence that CBD works better in combination with other cannabinoids (this is called the “entourage effect”).
Dosage is important, because CBD can have side effects—the most common are tiredness, diarrhea, and changes in appetite and weight—so it’s best not to take more than you need. As CBD becomes more prevalent, says J. Michael Bostwick, M.D., a psychiatrist at Mayo Clinic in Rochester, MN, “I’m reasonably certain new kinds of side effects will emerge.”
The scientific debate regarding taxonomy has had little effect on the terminology in widespread use among cultivators and users of drug-type Cannabis. Cannabis aficionados recognize three distinct types based on such factors as morphology, native range, aroma, and subjective psychoactive characteristics. Sativa is the most widespread variety, which is usually tall, laxly branched, and found in warm lowland regions. Indica designates shorter, bushier plants adapted to cooler climates and highland environments. Ruderalis is the informal name for the short plants that grow wild in Europe and Central Asia.