A recent Penn study found a correlation between marijuana use and sleep problems — but the study’s senior author said that other factors could play a role.
The study — which assessed responses to a 2007 to 2008 National Health and Nutrition Examination Survey by self-selecting people ages 20 to 59 — showed that any history of marijuana use is linked to impaired sleep quality. While the study only demonstrates correlation, not causation, results suggest that those who began using marijuana in adolescence have a much higher risk of sleep impediments as adults than those who did not.
“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,” said lead author Jilesh Chheda, who came up with the project idea, in a statement released by Penn Medicine.
Psychiatry instructor Michael Grandner, the senior study author, agreed that the risks of marijuana “seem to be the greatest for the youngest people.” However, he noted several potentially confounding variables that could have contributed to the correlation.
The abstract of the study states that those adults “who began after 18 years” most frequently experienced ‘severe nonrestorative sleep’ — a constant feeling of unrest during the day, no matter how much sleep one has the night before. This result is particularly applicable to college students, as many people become exposed to marijuana after they leave for college.
“If you think about it, [nonrestorative sleep] could be an effect [of cannabis use],” Grandner said. “If it’s mellowing people out during the day, they’ll probably feel sluggish no matter how much sleep they’re getting. That’s a possible explanation.”
The study’s abstract concluded that “frequent cannabis use is associated with impaired sleep quality. Initiation of cannabis use in adolescence may impart a higher risk for subsequent insomnia symptoms.”
However, as Grandner noted, people who begin using marijuana in adulthood are “fundamentally different” from people who begin using marijuana before the age of 15.
“Are those people on the same psychosocial stress trajectories as those [who begin using marijuana before the age of 15]? Probably not,” Grandner said.
Grandner noted another confounding variable between sleep and marijuana use may lie in people trying to solve pre-existing sleep conditions by self-medicating with marijuana, which may exacerbate the symptoms rather than solve the problem.
While writers ran amuck with the study’s results — Time magazine published an article titled “Marijuana use can bring sleepless nights, study finds” and the International Business Times wrote that “Marijuana could turn you into a nighttime ‘Walking-Dead’ zombie” — this study does not reveal causation, Grandner said, noting that other variables are “probably more likely” to impact sleep than marijuana use.
The study was published in Sleep magazine and is titled “Patterns of Marijuana (Cannabis) Use and Sleep Symptoms in American Adults.”
“Just like everything else in the world, there’s always a good and a bad, and it’s always better to know what the good and the bad is,” Grandner said of marijuana. “The truth is always more important than your agenda. [Right now] the evidence is not overwhelming in one direction or another.”