Surgery centers in every state should screen patients as routinely for marijuana use as they screen for cigarette smoking and alcohol consumption.

“When talking with patients coming to surgery at a same-day surgery center, the most important thing is to establish their use of marijuana in a preoperative profile,” says Bridget Petrillo, CRNA, who works for Greater Anesthesia Solutions LLC in Phoenix. “It’s one of the questions we regularly ask people now, especially in states where marijuana use is legal. We want to establish that use and how often they use it and, more specifically, when was the last time they used it.”

From the perspective of someone scheduling surgery, cannabis use is as important to know about as cigarette smoking, alcohol consumption, and prescriptions for diabetes and hypertensive medications. “All of those things impact the body and anesthesia. The medicines we give are all connected to that,” Petrillo says.

It is essential to know whether patients use cannabis or CBD products regularly, stresses Kevin Hill, MD, MHS, director, division of addiction psychiatry, Beth Israel Deaconess Medical Center, and associate professor of psychiatry, Harvard Medical School. Physicians should be straightforward when asking patients to disclose this information, suggests Edward Mariano, MD, MAS, professor of anesthesiology, perioperative and pain medicine, Stanford University.

Mariano says he approaches substance use screening with this script: “I’m a physician, and my specialty is making sure you are safe when you have surgery and making sure you have the best outcome and experience. When I ask you questions about the things you put in your body, I’m not passing any judgment. However, I need to know how the substances you put in your body may affect what I give you in anesthesia when you have surgery.”

Some drug-drug interactions are unpredictable, but others can be anticipated; still others can be avoided. “I have that open conversation, and patients respond really well to that,” Mariano says. “The doctor-patient relationship is still sacred, and the questions we ask are not to turn around and report them to the authorities. We’re taking their history and trying to understand what they do in their daily life and what substances they use on a daily basis, which is what we need to know before we can anesthetize them.”

In states where medical marijuana is legal, patients might not disclose their marijuana use to surgeons or other providers. “I don’t think patients are trying to mislead healthcare professionals,” Hill says. “But they either don’t think about it when they’re in the clinic because they are not asked about it, or they may believe their physician does not support the use of cannabis, so they’re not going to offer that information.”

With medical marijuana legal in almost three dozen states, there is less stigma surrounding its use than there might have been a decade ago. “I have noticed that it is becoming less stigmatized, and people are more open to [discussing] it,” Petrillo says.

A National Institute on Alcohol Abuse and Alcoholism survey revealed that the percentage of Americans reporting marijuana use doubled between 2001-2002 and 2012-2013. About 9.5% of American adults said they had used marijuana within the past year, and about 30% of the adults who use marijuana meet criteria for addiction.1

A more recent investigation revealed that marijuana use by middle-aged and older adults in the United States also had doubled.2 Doctors should ask about cannabis use for safety reasons.

“Whenever you ask people if they’re using — not only cannabis, but also cocaine or heroin — it’s a little discomforting,” says Karim Ladha, MD, MSc, assistant professor, anesthesia, University of Toronto. “Sometimes, we’ll say to people, ‘You don’t use any substances, right?’ and this discourages people from disclosing their use to us. Now that marijuana is legalized in Canada, people are asking the question more, and patients are more comfortable disclosing it as well.”

One way to screen for cannabis use is to make it a routine question. “It works well to ask people if they smoke cigarettes, drink alcohol, and the third question could be marijuana use,” Petrillo offers.

Clinicians should not stop with just asking whether someone uses marijuana. They need to ask specifically about cannabis products, CBD products, and edibles used for medicinal purposes. “Educate patients on the importance of telling us what we need to know about their [cannabis use],” Petrillo adds. “Maybe you could give them another opportunity to answer that question.” 


  1. National Institute on Alcohol Abuse and Alcoholism. Prevalence of marijuana use among U.S. adults doubles over past decade, Oct. 21, 2015. Available at:
  2. Han BH, Palamar JJ. Marijuana use by middle-aged and older adults in the United States, 2015-2016. Drug Alcohol Depend 2018;191:374-381.