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Visions Journal

A reminder that this article from our magazine Visions was published more than 1 year ago. It is here for reference only. Some information in it may no longer be current. It also represents the point of the view of the author only. See the author box at the bottom of the article for more about the contributor.

Cannabis Background

What is cannabis?

Reprinted from the "Cannabis" issue of Visions Journal, 2009, 5 (4), p. 7

Cannabis is the scientific name for the hemp plant. The hemp plant has roots, a stalk, leaves, flowers and seeds. There are three species of the hemp plant: Cannabis sativa, Cannabis indica and Cannabis ruderalis.

Cannabis stalks are fibrous and are used to make clothing, paper, textiles and fuel. Cannabis seeds contain essential fatty acids and are used for nutritional purposes. Cannabis leaves and flowers are used for medical and psychoactive (mind-altering) purposes.

Cannabis is commonly called marijuana, a slang word that originated in Mexico and refers only to the leaves and flowers of the hemp plant. Hemp typically refers to plants grown for fiber and seed.

The earliest record of cannabis use comes from Taiwan over 10,000 years ago. Today cannabis grows wild and is cultivated in many parts of the world. Breeders have developed hundreds of different strains of cannabis.

Cannabis is consumed in several forms, including:

  • dried flowers or ‘buds’ (marijuana)

  • pressed resin from flowers and leaves (hashish or hash)

  • loose resin (kief)

  • concentrated resin extracted with a solvent (hash oil)

Cannabis in these forms can be smoked in a joint or through a pipe or bong (water pipe). It can also be vapourized to produce a vapour instead of smoke. Sometimes cannabis is mixed with other herbs and smoked. Cannabis can be swallowed when added to cake, cookies and other foods or brewed into a tea or other beverage. It can be extracted into alcohol as a tincture and absorbed through the mucous membranes in the mouth. And it can be applied to the skin in a salve.

How does cannabis work?

Cannabis leaves and flowers have a resin containing unique chemicals called cannabinoids. There are more than 60 types of cannabinoids, but the best known is commonly called THC (delta-9-tetrahydrocannabinol). It has the most significant psychoactive effect. Concentrations of THC may range widely from plant to plant, but most contain 2–5% THC. Resin products typically contain 8–14% THC.

Cannabinoids fit into the body’s cannabinoid receptor sites found in the brain and other parts of the body, particularly in the nervous and immune systems. For example, cannabinoids bind to receptors on the pain centre of the brain and provide temporary relief. They suppress hormones normally produced in response to stress. They also stimulate an increase of dopamine in the brain. Dopamine is a naturally occurring chemical (neurotransmitter) which activates the brain’s "pleasure pathway."

When cannabis is inhaled, cannabinoids are absorbed through the lungs and into the bloodstream. The effects are felt within minutes and generally last a few hours. When swallowed, cannabinoids are absorbed through the stomach and travel through the body. The effects take longer to be felt, are stronger and last much longer.

Cannabis has different effects on different people. It can make one person feel calm and relaxed. It can make another person feel energized and stimulated. And it can make yet another person feel anxious and paranoid. The effects depend on many factors, including:

  • dosage

  • strain of cannabis

  • setting or environment

  • person’s history of use

  • person’s biochemistry

  • person’s mood or mindset

  • person’s diet

2009. Excerpted from Learn about Cannabis fact sheet developed the Centre for Addictions Research of BC for the BC Partners for Mental Health and Addictions Information.

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