Whatever its merits as a recreational drug or potential medication for pain or nausea, cannabis has long been touted for its soporific effect – a joint in the evening is followed by sound sleep until sun’s glint splits the curtains.
Or so the story goes. But a team of Northwestern University researchers has found evidence to clear some of the smoke that surrounds the presumption, with a 35-year study showing that many marijuana users suffer sleep disruptions that often go unnoticed.
In a paper published by the American Medical Association’s JAMA Network Open journal, the team said its tracking of participants from young adulthood to middle age showed that smoking weed is “associated with poorer objectively measured sleep quality, even though participants generally did not perceive their sleep to be worse.”
“This study challenges the common belief that cannabis helps people sleep better,” said Thanh-Huyen Vu, research associate professor of preventive medicine at Northwestern University Feinberg School of Medicine.
Study volunteers strapped a sleep monitor to their wrists and completed related surveys, which gave the researchers the comparative data to look at actual shut-eye and reported sleep side-by-side.
“Our findings suggest cannabis may actually be associated with poorer sleep quality, even if people don’t perceive those changes,” Vu explained.
“Cannabis-related sleep disruptions may go unnoticed by users themselves,” the team concluded.
The study could add more weight to the view that cannabis does not help against insomnia, though the jury largely remains out on the matter.
In a recent paper published in the medical journal Cochrane Database of Systematic Reviews, researchers at Universidad Hospital Italiano de Buenos Aires and University of Manitoba said they could not confirm that the drug either “improves sleep” or leads to better “daytime functioning.”
However, last year an Imperial College London team found that cannabis helped over 100 test participants who had reported having a sleep disorder.
A cannabis shop in Barcelona. Marijuana has long been associated with deep sleep, however researchers say there is no evidence to suggest it should be prescribed to insomnia patients. Paco Freire/SOPA Images via ZUMA Press Wire/dpa