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An Introduction to Substance Use Disorders for Dental Professionals

Course Number: 545


Cannabis (marijuana, hashish, and hash oil) is also known as weed, pot, reefer, joint, Mary Jane, ganja, grass, sinsemilla, and dope. Additionally, blunts are cigars emptied of some tobacco and refilled with marijuana. Marijuana has been described as the most commonly used illegal drug in the United States. In 2019, there were 30 million current users aged 12 and older, up from 19.8 million users in 2013..45 Marijuana laws are changing and may result in an increase in use. As of June 2019, eleven states (Alaska, California, Colorado, Illinois, Maine, Massachusetts, Michigan, Nevada, Oregon, Vermont and Washington) and the District of Columbia allow the recreational use of marijuana.3,36 Thirty-five states allow for the use of medical marijuana. To view a map of marijuana legalization status, visit

Marijuana increases dopamine, which creates the euphoria or “high” associated with its use. A user may feel the urge to smoke marijuana again and again to re-create that experience. Repeated use could lead to addiction – a disease where people continue to do something, even when they are aware of the severe negative consequences at the personal, social, academic, and professional levels.

Cannabis may be smoked as a cigarette or in a pipe, as well as added to foods. A favorite way to use marijuana is through a “bong” in which the smoke is drawn through a layer of water that cools the smoke and removes some of the tar and irritants.

When marijuana is smoked, tetrahydrocannabinol (THC) rapidly passes from the lungs into the bloodstream, which carries the chemical to the brain and other organs throughout the body.

Contrary to common belief, marijuana is addictive. Estimates from research suggest that about 9% of users become addicted to marijuana; this number increases to 17% among those who start young. People who use marijuana may also experience a withdrawal syndrome when they stop using the drug. This withdrawal is similar to what happens to tobacco smokers when they quit – people report being irritable, having sleep problems, and losing weight. Symptoms can last for several days to a few weeks after drug use is stopped. Relapse is common during this period, as users also crave the drug to relieve these symptoms.37

Cannabidiol (CBD) is the second most prevalent of the active ingredients of cannabis marijuana. While CBD is an essential component of medical marijuana, it is derived directly from the hemp plant, which is a cousin of the marijuana plant. While CBD is a component of marijuana (one of hundreds), by itself it does not cause a “high.” CBD has been used to reduce seizures, anxiety and chronic pain. CBD exhibits no effects indicative of any abuse or dependence potential.21 There is some evidence that CBD can be used to treat some addictive behaviors, however more research is necessary. 41 Synthetic marijuana (also known as synthetic cannabinoids or K2/Spice) is part of a group of drugs called new psychoactive substances (NPS). They are unregulated, have become newly available on the market, and are intended to produce the same effect as marijuana. Synthetic marijuana is human-made and contains mind-altering chemicals that are either sprayed on dried, shredded plant material so they can be smoked or sold as liquids to be vaporized and inhaled in e-cigarettes and other devices. These products are also known as herbal or liquid incense. Synthetic marijuana may be contaminated with other illicit drugs including opioids and/or methamphetamine.