Jump up ^ Crean RD, Crane NA, Mason BJ (March 2011). "An evidence based review of acute and long-term effects of cannabis use on executive cognitive functions". Journal of Addiction Medicine. 5 (1): 1–8. doi:10.1097/ADM.0b013e31820c23fa. PMC 3037578. PMID 21321675. Cannabis appears to continue to exert impairing effects in executive functions even after 3 weeks of abstinence and beyond. While basic attentional and working memory abilities are largely restored, the most enduring and detectable deficits are seen in decision-making, concept formation and planning.
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.
Laboratory evidence indicated that cannabidiol may reduce THC clearance, increasing plasma concentrations which may raise THC availability to receptors and enhance its effect in a dose-dependent manner. In vitro, cannabidiol inhibited receptors affecting the activity of voltage-dependent sodium and potassium channels, which may affect neural activity. A small clinical trial reported that CBD partially inhibited the CYP2C-catalyzed hydroxylation of THC to 11-OH-THC.
Today, 30 countries around the world allow farmers to grow industrial hemp, China being the largest producer and exporter. Canada, which produces hemp for food and toiletries, legalized the crop in 1996. The US, on the other hand, has restricted hemp production and categorized hemp in Schedule 1 of the Controlled Substances Act, attributing it as a relative of marijuana.
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