What is it?

Marijuana, also commonly known as reefer, pot, herb, ganja, and weed, is a highly varied drug used in many forms. It comes from the cannabis plant, which contains over four hundred chemicals, the most psychoactive being delta-9-tetrhydrocannibinol, or THC. Most forms of marijuana contain 2-5% THC concentration, although some, such as hash oil contain THC concentrations of 20-70%. The leaves of the cannabis plant are dried to make marijuana which are then inhaled through the lungs by smoking (joints, bongs) or ingested through the mouth by eating (edibles). Other parts of the plant are processed into hash, oil, or tar, which all contain THC. In our discussion of marijuana, THC will be the most important chemical that leads to many of the effects experienced by users.

What are the effects?

Users of marijuana report feelings of extreme relaxation, euphoria, and intensified sensory awareness during a high. Marijuana use can also lead to paranoia, hallucination, and anxiety. The physiological effects of marijuana depend on the way a user administers it and on what kind of marijuana is being used. We will focus on the most common ways that marijuana is used: by smoking and eating. When smoked, blood lining the lungs absorbs THC immediately and the chemical moves directly to the brain. This causes heart rate and blood pressure to increase, and the effects of the drug to be felt immediately. The smoke inhaled from weed goes into a user’s lungs very deeply (2/3 more marijuana ingested per puff as compared to a puff of tobacco). When eaten, marijuana takes a much longer time to reach the brain, and the effects are therefore not felt as quickly. Edibles result in a more gradual sensation of high that lasts longer than smoking. Eating marijuana also results in higher levels of THC in the bloodstream because a greater dose of marijuana is typically consumed when eaten. THC is hard to break down, and 30% of THC ingested remains a week after marijuana use.

What are the risks?

There is a cannabinoid receptor in our brain that plays a role in learning and control of anxiety. The hippocampus, a part of the brain involved in memory formation, has a high concentration of these receptors. As a result, marijuana decreases the brain’s ability to learn make new memories, which is why things users learn while high on marijuana are often forgotten. Cannabinoid receptors are also found in the cerebellum, responsible for body movement and coordination, which is why marijuana use has been correlated with car accidents. Marijuana use also puts a user at risk of psychological addiction/tolerance, increased anxiety, and lung/heart problems. Because the cannabis plant contains hundreds of chemicals, and even more carcinogens are made when marijuana is burned while smoking, marijuana use can lead to toxins with various effects entering the body. Although there has been no report of physical dependence or lethal overdose, marijuana users are at risk of psychological dependence.