Two recent studies have raised doubts about whether cannabis can help people sleep better. One review found little evidence of benefit for adults with insomnia, while a separate long-term study linked regular use to poorer sleep quality.
In the first study, researchers pooled data from nine trials involving 537 adults with insomnia. Participants had been randomly assigned to medical cannabis, a placebo or an antidepressant. The researchers reported on Tuesday in The Cochrane Database of Systematic Reviews that medical cannabis produced little to no clinically meaningful improvement in sleep quality, satisfaction, total sleep time or daytime functioning.
Limits of the cannabis insomnia trials
The researchers noted that the trials used different cannabis products, and none followed participants for more than 12 weeks. They also rated the overall quality and certainty of the evidence as very low to low, citing possible bias and other limitations. As a result, they said the findings cannot reliably show whether medical cannabis helps people with insomnia.
Study leader Dr. Luis Garegnani, from Universidad Hospital Italiano de Buenos Aires in Argentina, urged caution. “Rather than viewing the findings as either an endorsement or a rejection of medical cannabis, clinicians and patients should recognize the uncertainty and consider individual circumstances while better evidence is generated,” he said in a statement.
Long-term use linked to disrupted nights
A separate study published in JAMA Network Open followed 1,266 participants from young adulthood into middle age. It found that long-term cannabis use was linked to lower sleep quality, as measured by wrist-worn monitors. The findings also suggested that users may not notice these sleep disruptions.
Dr. Thanh-Huyen T. Vu of Northwestern University Feinberg School of Medicine said the devices detected more nighttime disruption among long-term users, but those participants generally did not report worse sleep. She said the study challenges the common belief that cannabis helps people sleep better, and that cannabis may be linked to poorer sleep quality even when people do not perceive the changes.
