Concerns About Cannabis

A May 2024 study published in the journal Addiction found that more Americans are using cannabis, a.k.a. marijuana, daily than are using alcohol.

“Cannabis use has increased tremendously, due to both decriminalization at the federal level and legalization in some states,” says Yakir Vaks, MD, service chief of the adult co-occurring disorders unit at Sheppard Pratt. Currently, 38 states and Washington, D.C., have enacted medical marijuana programs, while 24 states and the district allow adult recreational use.

That means that clinicians need to be having conversations with their patients about their use of cannabis.

“The first issue that should be on our minds is how to conceptualize cannabis,” says Christoffel Le Roux, MD, lead physician of the co-occurring disorders track at The Retreat by Sheppard Pratt. “And the first question a psychiatrist should ask themselves is what their perspective is on marijuana use—not just for someone with a substance use disorder, but anyone with a mental health condition.”

Cannabis risks

Additives 

What’s “in” marijuana is a major issue of concern, one not found with prescription medicine, says Dr. Le Roux. “It isn’t regulated the same way as pharmaceutical drugs, but patients think, ‘Well, if the government approves this, it must be a great idea.’”

“When marijuana is bought on the street, it can contain mixtures of a variety of things: anything from opioids to stimulants to other synthetic drugs,” says Dr. Vaks. “Even when a patient is purchasing from a dispensary, cannabis products are difficult to know what you’re getting because it’s derived from a plant.”

Dispensaries typically monitor their supply chains, he says. “But people who get marijuana from the wrong places can end up in the hospital sick, both psychiatrically and physically.”

Beyond concerns about additives, the content of delta-9-tetrahydrocannabinol (THC) in marijuana is much higher than decades ago. From the 1960s to the 1980s, THC content was less than 2%. Between 1995 and 2015, THC content in the marijuana flower increased 212%, according to a study in the journal Missouri Medicine. The National Institute on Drug Abuse says samples it seized showed 3.96% THC in 1985, and 16.14% in 2022.

Negative effects 

Cannabis can cause altered perception of time and impaired thinking, memory, and body movement, says the National Institute on Drug Abuse. It can also make people feel more irritable or restless.

Dr. Le Roux does not recommend his patients use cannabis. “I believe that any substance such as marijuana for anyone who has a mental health condition, or is predisposed to one, is not going to get them on the path to success, and may, in fact, lead to greater problems—including issues with family, employment, and finances,” he says.

“That said, cannabis has some clinical benefits for certain patient populations,” Dr. Vaks says.

For example, cannabis may help with nausea for those on chemotherapy. “Some children with seizure conditions respond to cannabinoid-type medications such as FDA-approved Marinol better than other antiseizure medications.”

Demographic differences

Retirees with disposable income, who remember when “Mary Jane” was fun to smoke, might want to try it again. “We need to remind them about the increased strength, and that the ‘nice experience’ they had then may not be the same now,” says Dr. Vaks.

Marijuana may negatively interfere with brain development in younger people, he says. 

“We have evidence around marijuana impacting IQ, impacting their ability to achieve their full potential.”

Comorbidities 

“Previous major studies have found a statistical association between cannabis use and the development of schizophrenia and other psychotic disorders, with the highest risk among the most frequent users,” says Dr. Le Roux.

He views development of schizophrenia as a “nature/nurture dynamic.”

“You need the genetic vulnerability, and you need the stress of the environment,” he says. “When genetics and stress meet, boom! Schizophrenia. Add cannabis to the mix, and it just makes that ‘boom’ easier.”

“There does appear to be a genetic component for those predisposed to developing psychosis,” Dr. Vaks says. “I tell my patients this is a risk. I have seen a few patients exposed to cannabis at a young age who developed psychosis that didn’t resolve when use was stopped.”

Early onset of symptoms means a longer-term illness.

Cannabis use is also associated with increased rates of depression, anxiety, and suicide, says Dr. Le Roux.

Don’t forget the statistical association between marijuana smoking and serious respiratory symptoms, with frequent chronic episodes, coughing, wheezing, increased rates of pneumonia, and upper respiratory infections, Dr. Vaks says.

Medication interactions 

“Psychoactive substances may interfere with the way medications work,” Dr. Vaks says. “I explain that to patients and say, ‘if this impedes your progress, I expect you to stop.’”

That conversation is best conducted when a patient can really listen, not when they are acutely hospitalized, he says.

“At Sheppard Pratt, we welcome whatever patients bring us, and then we educate them,” says Dr. Le Roux. “It’s like Maya Angelou says: ‘When we know better, we do better.’ Patients do the best they can with what they know.”