MINNEAPOLIS—Marijuana use is associated with impaired sleep quality, according to research presented at the 28th Annual Meeting of the Associated Professional Sleep Societies. A history of cannabis use appears to be associated with an increased likelihood of reporting difficulty falling asleep, difficulty maintaining sleep, experiencing nonrestorative sleep, and feeling daytime sleepiness.
The strongest association was found in adults who started marijuana use before age 15. They were approximately twice as likely to have severe problems falling asleep (odds ratio [OR], 2.28), to experience nonrestorative sleep (OR, 2.25), and to feel excessively sleepy during the day (OR, 1.99). The only association found in participants who began using marijuana after age 18 was with severe nonrestorative sleep (OR, 1.67).
Results were adjusted for potential confounders, including age, sex, race or ethnicity, and education. Michael Grandner, PhD, Instructor in the Division of Mood and Anxiety Disorders at the University of Pennsylvania in Philadelphia, supervised the research.
“Current and past marijuana users are more likely to experience sleep problems,” said Jilesh Chheda, research assistant at the University of Pennsylvania. “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 between ages 20 and 59 who responded to the 2007–2008 National Health and Nutrition Examination Survey. A total of 1,811 participants reported a history of drug use. Information about cannabis use included any history of use, age at first use, and number of times used in the past month. The researchers considered sleep-related problems severe if they occurred at least 15 days per month.
Although the design of this study did not allow for an examination of causality, the results suggest that initiation of marijuana use in adolescence may impart a higher risk for subsequent insomnia symptoms. An alternative interpretation is that people who begin using marijuana earlier are more likely to experience insomnia for other reasons, such as stress. Insomnia may be one reason that people start or continue use, although the evidence suggests that marijuana probably is not effective for this indication.
“Marijuana use is common, with about half of adults having reported using it at some point in their life,” said Mr. Chheda. “As it becomes legal in many states, it will be important to understand the impact of marijuana use on public health, as its impact on sleep in the real world is not well known.”