The most valid claims to environmental friendliness of hemp are with respect to agricultural biocides (pesticides, fungicides, herbicides). Cannabis sativa is known to be exceptionally resistant to pests (Fig. 51), although, the degree of immunity to attacking organisms has been greatly exaggerated, with several insects and fungi specializing on hemp. Despite this, use of pesticides and fungicides on hemp is usually unnecessary, although introduction of hemp to regions should be expected to generate local problems. Cannabis sativa is also relatively resistant to weeds, and so usually requires relatively little herbicide. Fields intended for hemp use are still frequently normally cleared of weeds using herbicides, but so long as hemp is thickly seeded (as is always done when hemp is grown for fiber), the rapidly developing young plants normally shade out competing weeds.
Most human studies of CBD have been done on people who have seizures, and the FDA recently approved the first CBD-based drug, Epidiolex, for rare forms of epilepsy. Clinical trials for other conditions are promising, but tiny. In one Brazilian study published in 2011 of people with generalized social anxiety disorder, for example, taking a 600-mg dose of CBD (higher than a typical dose from a tincture) lessened discomfort more than a placebo, but only a dozen people were given the pill.
Jump up ^ Blest-Hopley G, Giampietro V, Bhattacharyya S (May 2018). "Residual effects of cannabis use in adolescent and adult brains - A meta-analysis of fMRI studies". Neuroscience and Biobehavioral Reviews. 88: 26–41. doi:10.1016/j.neubiorev.2018.03.008. PMID 29535069. This may reflect the multitude of cognitive tasks employed by the various studies included in these meta-analyses, all of which involved performing a task thereby requiring the participant to reorient their attention and attempt to solve the problem at hand and suggest that greater engagement of this region indicates less efficient cognitive performance in cannabis users in general, irrespective of their age.
^ Jump up to: a b Weinstein A, Livny A, Weizman A (2016). "Brain Imaging Studies on the Cognitive, Pharmacological and Neurobiological Effects of Cannabis in Humans: Evidence from Studies of Adult Users". Current Pharmaceutical Design. 22 (42): 6366–6379. doi:10.2174/1381612822666160822151323. PMID 27549374. 1)The studies reviewed so far demonstrated that chronic cannabis use has been associated with a volume reduction of the hippocampus...3)The overall conclusion arising from these studies is that recent cannabis users may experience subtle neurophysiological deficits while performing on working memory tasks, and that they compensate for these deficits by "working harder" by using additional brain regions to meet the demands of the task.
What is cannabis?Cannabis is a drug that comes from Indian hemp plants such as Cannabis sativa and Cannabis indica. The main active chemical in cannabis is THC (delta-9 tetrahydrocannabinol).Cannabis is a depressant drug. Depressant drugs do not necessarily make you feel depressed. Rather, they slow down the activity of the central nervous system and the messages going between the brain and the body. When large doses of cannabis are taken it may also produce hallucinogenic effects.For information on synthetic cannabinoids, see our "Legal high" facts page.Other namesCannabis is also known as grass, pot, hash, weed, reefer, dope, herb, mull, buddha, ganja, joint, stick, buckets, cones, skunk, hydro, yarndi, smoke and hooch.What does cannabis look like?Leaves from the cannabis plant are bright green and have a distinctive shape with five or seven leaflets. The flowering tops and upper leaves are covered in a sticky resin.Cannabis is used for the psychoactive (mind and mood-altering) effects of THC and other active ingredients. THC is the chemical in cannabis that makes you feel “high”.There are three main forms of psychoactive cannabis: marijuana, hashish and hash oil.Marijuana is the most common and least potent form of cannabis. Marijuana is the dried leaves and flowers of the plant.Hashish (“hash”) is dried cannabis resin, usually in the form of a small block. The concentration of THC in hashish is higher than in marijuana, producing stronger effects.Hash oil is a thick, oily liquid, golden brown to black in colour, which is extracted from cannabis. Hash oil is the strongest form of cannabis.How and why is it used?The different forms of cannabis are used in different ways:Marijuana is smoked in hand-rolled cigarettes (joints), or in a pipe (a bong).Hashish is usually added to tobacco and smoked, or baked and eaten in foods such as hash cookies.Hash oil is usually spread on the tip or paper of a cigarette and then smoked.Cannabis and hash can also be smoked in a vaporiser. Vaporisers heat cannabis to temperatures that release its active ingredients while minimising the toxins associated with burning.The THC in cannabis is absorbed into the bloodstream through the walls of the lungs (if smoked), or through the walls of the stomach and intestines (if eaten). The bloodstream carries the THC to the brain, producing the “high” effects. Drugs inhaled get into the bloodstream quicker than those eaten. This means that the effects of cannabis when smoked occur more rapidly than when eaten.Paper and textilesSome species of cannabis have few psychoactive effects. These plants are used to produce hemp fibre for use in paper, textiles and clothing.Medical usesCannabis has been used for medical purposes for many centuries. It has been reported that cannabis may be useful to help conditions such as:nausea and vomiting, particularly when associated with chemotherapywasting and severe weight loss, in people with HIV/AIDS, cancer, or anorexia nervosa, as it may be used as an appetite stimulantpain relief, for example in people with cancer and arthritisrelief from symptoms of some neurological disorders that involve muscle spasms, including multiple sclerosis and spinal cord injuryglaucomaepilepsyasthma.For more information, please click on the Australian Drug Foundation's DrugInfo Clearinghouse web site link below.
Dehulled (i.e. hulled) hemp seed is a very recent phenomenon, first produced in quantity in Europe. Hemp seeds have been used as food since ancient times, but generally the whole seed, including the hull, was eaten. Hemp seed was a grain used in ancient China, although there has been only minor direct use of hemp seed as food by humans. In the past, hemp seed has generally been a food of the lower classes, or a famine food. Peanut-butter type preparations have been produced from hemp seed in Europe for centuries, but were rather gritty since technology for removing the hulls was rudimentary. Modern seed dehulling using mechanical separation produces a smooth, white, gritless hemp seed meal that needs no additional treatment before it is consumed. It is important to understand, therefore, that the quality of modern hemp seed for human consumption far exceeds anything produced historically. This seed meal should be distinguished from the protein-rich, oil-poor seed cake remaining after oil has been expressed, that is used for livestock feed. The seed cake is also referred to as “seed meal,” and has proven to be excellent for animals (Mustafa et al. 1999).
In the United States, the CBD drug Epidiolex has been approved by the Food and Drug Administration for treatment of two epilepsy disorders.[13] The U.S. Drug Enforcement Administration has assigned Epidiolex a Schedule V classification while non-Epidiolex CBD remains a Schedule I drug prohibited for any use.[14] CBD is not scheduled under any United Nations drug control treaties, and in 2018 the World Health Organization recommended that it remain unscheduled.[15]
Hemp is grown in temperate zones as an annual cultivated from seed and can reach a height of up to 5 metres (16 feet). Crops grow best in sandy loam with good drainage and require average monthly rainfall of at least 65 mm (2.5 inches) throughout the growing season. Crops cultivated for fibre are densely sowed and produce plants averaging 2–3 metres (6–10 feet) tall with almost no branching. Plants grown for oilseed are planted farther apart and are shorter and many-branched. The slender stalks are hollow except at the tip and base. The leaves are compound with palmate shape, and the flowers are small and greenish yellow. Seed-producing flowers form elongate, spikelike clusters growing on the pistillate, or female, plants. Pollen-producing flowers form many-branched clusters on staminate, or male, plants. Maximum yield and quality are obtained by harvesting soon after the plants reach maturity, indicated by the full blossoms and freely shedding pollen of the male plants. Although sometimes pulled up by hand, plants are more often cut off about 2.5 cm (1 inch) above the ground.
This summary is reviewed regularly and updated as necessary by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, which is editorially independent of the National Cancer Institute (NCI). The summary reflects an independent review of the literature and does not represent a policy statement of NCI or the National Institutes of Health (NIH).
She also believes that the Senate's Farm Bill would alleviate confusion caused by the US Drug Enforcement Agency (DEA)'s issuance of conflicting “guidance” to state and federal agencies, which leaves them "scratching their heads," and often "bullies them into making decisions that directly contradict the legislative intent and spirit of the last version of the Farm Bill," Beckerman said.
There is great variation in Cannabis sativa, because of disruptive domestication for fiber, oilseed, and narcotic resin, and there are features that tend to distinguish these three cultigens (cultivated phases) from each other. Moreover, density of cultivation is used to accentuate certain architectural features. Figure 5 illustrates the divergent appearances of the basic agronomic categories of Cannabis in typical field configurations.

Hemp, or industrial hemp (from Old English hænep),[1] typically found in the northern hemisphere, is a variety of the Cannabis sativa plant species that is grown specifically for the industrial uses of its derived products.[2] It is one of the fastest growing plants[3] and was one of the first plants to be spun into usable fiber 10,000 years ago.[4] It can be refined into a variety of commercial items including paper, textiles, clothing, biodegradable plastics, paint, insulation, biofuel, food, and animal feed.[5]