COVID-19 Resource Center

Review the latest information on visitor policies, safety procedures, vaccines, and more in the COVID-19 Resource Center.


Marijuana and Your Health

Medical Implications of Cannabis Use

Cannabis is a plant made up of different components called cannabinoids, which can be consumed in a variety of ways, from smoking to ingesting. Two of the most common cannabinoids are:

  • Cannabidiol (CBD), which is non-psychoactive, meaning it will not give users a “high.”
  • Tetrahydrocannabinol (THC), a psychoactive component associated with a “high.”

Illinois is the 11th state to legalize recreational marijuana for adults. With statewide legalization effective January 1, 2020, adults 21 years and older can possess cannabis and purchase cannabis products in licensed stores. Possession for state residents is limited to:

  • 30 grams of raw cannabis
  • Cannabis-infused product or products containing no more than 500 mg of THC
  • 5 grams of cannabis product in concentrated form

Non-residents may purchase half of these amounts.

Patrick M. Lank, MD, is an emergency medicine physician and medical toxicologist at Northwestern Memorial Hospital. Dr. Lank’s interests include novel substances of misuse and critical care for overdose. Here, Dr. Lank answers frequently asked questions about cannabis and health care.

Q: Who is most at risk for the adverse effects of cannabis use?

A: “Pediatric and psychiatric patients are at a particular risk. Of concern is an increase in children under 12 exposed to it, primarily through edibles and accidentally.

“Novice adult cannabis users may also experience anxiety and other psychotic symptoms such as paranoia and hallucinations. Young adults who start using cannabis regularly are at a higher risk of developing psychiatric disorders like depression and anxiety. Additionally, it can trigger or worsen the psychotic symptoms of schizophrenia, like hallucinations, paranoia and psychosis.”

Q: What are the medical implications of chronic, long-term marijuana use?

A: “Cannabinoid hyperemesis syndrome is a life-changing syndrome that can develop in patients with chronic marijuana use. It involves cyclic vomiting, abdominal pain and a desire to take hot baths or showers. It’s hard to treat because patients think marijuana will help with their nausea when symptoms really return and worsen if patients continue to use cannabis. It can take two weeks to months after patients stop using cannabis for symptoms to stop. The cause of this syndrome is unknown. In the emergency department, we treat the symptoms of this syndrome, most commonly dehydration and electrolyte abnormalities. I try to open a discussion about cessation with these patients.”

Q: Can I become addicted to cannabis?

A: “Yes. A lot of people don’t believe you can be addicted to it. But approximately 9 percent of lifetime users meet criteria for a use disorder, previously called dependence. Cannabis is one of the most common substances for which people seek substance abuse counseling.”

Q: Is smoking cannabis safer than smoking cigarettes?

A:“Smoking is smoking. Just because cannabis comes from a plant doesn’t mean it’s safe. Smoking marijuana can increase your risk of chronic lung disease and lung cancer. I tell family, friends and patients that they should never ingest THC via vape pen or e-cigarette due to the risk of vaping-related lung injury and the danger of the additive, vitamin E acetate.”

Q: What are the best safety practices for using cannabis products?

A:“If you’re going to consume cannabis, don’t drive. Keep products in a locked safe box at home, particularly if you have young children. Do not use cannabis products while pregnant. Never use cannabis products in the presence of children. Children should not see you take edibles or be around you when you smoke cannabis to avoid the risk of secondary high from smoke exposure.”

Q: Should I tell my physician that I’m using cannabis?

A: “Yes. Cannabis use history is just as important as your smoking and drinking history for your physician to know. Physicians are still trying to wrap their heads around how cannabis affects preexisting health conditions and interacts with medications. Because this relationship is so complex, it’s important to be honest with your physician about cannabis use.”