PHILADELPHIA — A new study from researchers at the Perelman School of Medicine at the University of Pennsylvania suggests that marijuana use may be associated with impaired sleep quality, especially in people who have been using the drug since their teenage years. The research abstract was published recently in an online supplement of the journal Sleep and will be presented at SLEEP 2014, the 28th annual meeting of the Associated Professional Sleep Societies LLC.

“While prior research has shown that many people report using marijuana to relax and possibly as a sleep aid, this latest study found that current and past marijuana users are more likely to experience sleep problems,” said lead author Jilesh Chheda, research assistant, Division of Mood and Anxiety Disorders, Department of Psychiatry at Penn. “The most surprising finding was that there was a strong relationship with age of first use, no matter how often people were currently using marijuana. People who started using early were more likely to have sleep problems as an adult.”

The study involved adults ranging in age from 20-59 years who responded to the 2007-2008 National Health and Nutrition Examination Survey (NHANES). A history of drug use was reported by 1,811 participants. Cannabis use was assessed as any history of use, age at first use and number of times used in the past month. Sleep-related problems were considered severe if they occurred at least 15 days per month.

Results show that any history of cannabis use was associated with an increased likelihood of reporting difficulty falling asleep, struggling to maintain sleep, experiencing non-restorative sleep, and feeling daytime sleepiness. The strongest association was found in adults who started marijuana use before age 15; they were about twice as likely to have severe problems falling asleep, experiencing non-restorative sleep and feeling overly sleepy during the day.

The research team notes that the study was not designed to determined causality, so they cannot determine the exact relationship between marijuana use and sleep disturbance. The new finding may have important implications given that marijuana is one of the most commonly used drugs in the U.S., with a higher prevalence of use in adolescents, and marijuana use has also become legal in some states. “As more people have access, it will be important to understand the implications of marijuana use on public health, as its impact on sleep in the ‘real world’ is not well known,” said senior study author, Michael Grandner, PhD, instructor in Psychiatry and member of the Center for Sleep and Circadian Neurobiology.

The study was supported by funding from the National Heart, Lung and Blood Institute; the National Institute of Environmental Health Sciences; and the University of Pennsylvania Clinical and Translational Science Award.

For more information, please see the AASM press release.