Can Weed Help You Sleep Better? The Truth About How Cannabis Affects Your Health

There’s a major lack of conclusive research on how cannabis actually affects the body, which has led to over-the-top claims, both pro and con. We asked experts to help clear the air.

by
Blonde woman with black polish smokes a joint, (health effects pot sleep cancer sex)

Photo, Mayara Klingner/EyeEm/Getty Images.

Is weed addictive?

The answer, scientifically speaking, is yes — but only for a relatively small percentage of users.
“Best estimates suggest that about 10 percent of people who use will develop something that looks like dependence at some point in their lives,” says M-J Milloy, a scientist with the BC Centre on Substance Use and an assistant professor in the department of medicine at the University of British Columbia. “That’s much lower than heroin, cocaine and tobacco, for that matter.” Still, says Milloy, the psychological effects can be profound: “If you’re running into problems because you’re using it too often, that might indicate
a problem.”

Is it dangerous to drive when using cannabis?

In a word, yes. “Cannabis intoxication obviously interferes with your perception and motor skills,” says Milloy. “It definitely doesn’t make you a better driver.” Microdosing, along with the growing popularity of low-THC strains, complicates the picture a bit. THC at any level slows reaction time. But do extremely low doses have measurable effects on driving ability? The science isn’t certain, but we do know that the amount of THC in your blood isn’t a reliable indicator of how high you are, which makes blood testing pretty useless. Unlike alcohol, THC impairment can vary greatly, depending on
the person.

Does marijuana affect your sex drive?

The data is thin, with a few exceptions. Stanford University researchers recently looked at more than 50,000 cannabis users ages 25 to 45 and found that they had sex more frequently than non-users and no link to impaired sexual function. The researchers warned, though, that it didn’t prove a causal relationship. A Danish study in 2015 found that weekly cannabis smoking was associated with a 29 percent lower sperm count.

Can cannabis cause lung cancer (or other cancers)?

“Inhaling flame bits of plant matter always carries those risks,” says Milloy. “But many of the links to cancer have to do with smoking rather than with cannabis itself.” Studies back this up: A 2015 meta-analysis of research found no link between head and neck cancers and cannabis use. Similar studies on other cancers have shown no link or, at most, very weak or uncertain links.

But wait, can it cure cancer?

Milloy points at promising research that suggests some cannabinoids might be helpful in treating some brain tumours. “But going from what works in a test tube to using as a treatment for humans is a long, difficult process,” he says. “We haven’t gotten that far yet. The idea that it constitutes a treatment in itself is extremely misleading.”

Will weed help or disrupt your sleep?

Some studies have shown that the cannabinoid compound THC is associated with falling asleep faster, while others have connected low doses of CBD with wakefulness and high doses with sleepiness. Some insomnia sufferers use high-CBD strains to fall asleep, says Rebecca Haines-Saah, an assistant professor in the department of community health science at the University of Calgary, who specializes in drugs and substance use. A large-scale review of existing research conducted last year concluded that high-dose CBD and low-dose THC may help you drift off quicker and improve sleep quality. But if you’re a regular user, you might get habituated to the effects.