Marijuana use is associated with daytime sleepiness and impaired sleep quality at night, a new study led by an Indian-origin scientist has found.
Researchers found 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.
“Current and past marijuana users are more likely to experience sleep problems,” said lead author Jilesh Chheda, research assistant at the University of Pennsylvania in Philadelphia, working with Dr Michael Grandner, the senior author on the study.
“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,” Chheda said.
The study involved adults ranging in age from 20-59 years who responded to the 2007-2008 National Health and Nutrition Examination Survey (NHANES) in the US.
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.
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, or it may mean that those who begin using earlier are more likely to experience insomnia for other reasons, such as stress.
Insomnia may even be one of the reasons people start (or continue) use, though this evidence suggests that it is probably not effective if they are still experiencing problems.
The research abstract was published in the journal Sleep and will be presented at SLEEP 2014, annual meeting of the Associated Professional Sleep Societies LLC, in Minneapolis, Minnesota.