More than 1 in 5 young adults in the United States are using cannabis or alcohol as a sleep aid, new research shows.

Every two years, researchers from the University of Michigan survey 20,000 adults 19 to 30 as part of an ongoing study of health behaviors.

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The latest findings, published in JAMA Pediatrics, show that 22% of participants either used cannabis or alcohol, or both, to help them fall asleep — habits that can have a series of negative repercussions, the researchers said.

“Using these substances to get to sleep can backfire because they can interfere with the ability to stay asleep and with the quality of sleep,” Megan Patrick, the study’s principal investigator, said in a news release. “They appear to actually disrupt sleep in the long term.”

More people reported using marijuana for sleep than alcohol. Among the respondents, 18% said they used cannabis as a sleep aid; 7% said they used alcohol for the same purpose.

Patrick called the findings about marijuana “alarming.”

People who use cannabis and alcohol on a regular basis for sleep can develop a tolerance to these substances, meaning they will need to consume increasing amounts to get the same effect over time. Also, using these substances as sleep aids puts people at risk of developing substance use disorders, Patrick said.

Health care providers should better understand how young people are using alcohol and weed for sleep and should advise patients about the risks involved, Patrick said.

Drinking alcohol, even in moderation, increases the risk of at least seven types of cancer, research shows. The World Health Organization published a statement in 2023 saying that there is no safe level of alcohol consumption.

Marijuana use can lead to increased risk of stroke, heart disease, mental health issues, cognitive function and lung problems, according to the Centers for Disease Control and Prevention.

Adults 18 to 60 should get at least seven hours of sleep a day, according to CDC guidelines.

To improve sleep without the use of substances, Harvard Health recommends:

• Going to bed and waking up at the same time each day
• Creating a dark, cool, relaxing environment for sleep
• Eating dinner at least three hours before bedtime
• Avoiding caffeine after breakfast
• Avoiding smoking and drinking
• Getting enough exercise during the day