When it comes to polarizing health topics, few subjects spark more debate than weed (except maybe CrossFit or the Paleo Diet). Can it improve your health? Lower stress? Make you more forgetful? Even make you skinnier?
The science is still, well, hazy—but some research is starting to give us an idea of what exactly weed does to the human body.
For instance: Toking up regularly could dull your emotional response and cause addiction, according to a marijuana study from the University of Michigan Health System. Researchers analyzed 108 people in their early 20s (69 men and 39 women), all of whom were taking part in a larger study of substance use. In the study, participants sat in an MRI while they played a game, in which they pressed a button when they saw a target on a computer screen cross in front of them. Before each round, they were told they could win 20 cents or $5—or they might lose that amount, or have no reward or loss. Scientists assessed the moment of anticipation (a.k.a. when volunteers knew they could get a few dollars richer).
Now, you’d think getting free money would be cause for excitement, but scientists found the more marijuana use volunteers reported, the less their reward centers were activated.
“Over time, marijuana use was associated with a lower response to a monetary reward,” study author and neuroscientist Mary Heitzeg, Ph.D, said in a press release. “This means that something that would be rewarding to most people was no longer rewarding to them, suggesting but not proving that their reward system has been ‘hijacked’ by the drug, and that they need the drug to feel reward—or that their emotional response has been dampened.”
That’s not all. Smoking weed might also be more addicting than you think.
“Some people may believe that marijuana is not addictive or that it’s ‘better’ than other drugs that can cause dependence,” Heitzeg said. “But this study provides evidence that it’s affecting the brain in a way that may make it more difficult to stop using it. It changes your brain in a way that may change your behavior, and where you get your sense of reward from.”
To be fair: Even if one scientific study suggests that marijuana might help your bones grow or hurt your short-term memory, that doesn’t necessarily make it true. All this research is still developing, and it’ll be a long time before we know anything for sure about weed’s effects on the human body. Still, it’s good to know where the science is heading.
Find out all the other ways—good and bad—marijuana could be influencing your health.
1. It can damage blood vessels
Secondhand smoke may not seem all that bad. But it can have a major impact on your blood vessels, according to research from the American Heart Association. After rats inhaled secondhand smoke for one minute, their arteries carried blood less efficiently for at least 90 minutes. When they were exposed to secondhand tobacco smoke, however, their blood vessels recovered after 30 minutes. “While the effect is temporary for both cigarette and marijuana smoke, these temporary problems can turn into long-term problems if exposures occur often enough and may increase the chances of developing hardened and clogged arteries,” said study author Matthew Springer, Ph.D.
2. It may increase testicular cancer risk
Smoking weed may increase your odds of getting testicular cancer, researchers at the University of Southern California found. In the study, men who had testicular germ cell tumors were more likely to report previously using marijuana than those who didn’t have the tumors. While the findings were interesting, more research needs to be done to determine if there was a causal relationship between cancer and marijuana use, a doctor for the American Cancer Society said that .
3. It impacts short-term memory
Stoners get a bad reputation for being forgetful, but it turns out the stigma might not be entirely myth. In one study, Northwestern University scientists found that former pot smokers had developed brain abnormalities in regions associated with short-term memory, and performed slightly worse on memory-related tasks. Even more unsettling: The brains of pot smokers were found to be abnormally shaped and looked similar to brains damaged by schizophrenia. (That’s not to say that smoking weed causes schizophrenia, of course, and obviously a lot of research still needs to be done on the topic.)
4. It hinders creativity
Artists, musicians, and other creative types sometimes credit marijuana as their source of inspiration. However, a study from the Netherlands seems to prove otherwise. Volunteers who were given marijuana with high THC content were not able to come up with as many solutions to a problem as those given a placebo.
5. It could destroy brain cells
All those jokes about stoners killing their brain cells? They might have some merit, according to a 20-year study on smoking pot, which suggests that lighting up could decrease cognitive function, in addition to an increased risk of psychotic symptoms and disorders.
6. It could help heal broken bones
It’s not all bad news for pot smokers. Weed may help bones heal stronger and faster, according to a study from Tel Aviv University. Cannabinoid cannabidiol, which is found in cannabis leaves and stems, helped mice recover from broken bones more effectively. Researchers believe the substance helps minerals get into the bone tissue, making bones stronger, sturdier, and less likely to break in the future.
7. It isnt great for your job prospects
If you want to be successful, then you better lay off the weed, according to scientists at UC Davis and Duke. “People who smoked cannabis four or more days of the week over many years ended up in a lower social class than their parents, with lower-paying, less skilled, and less prestigious jobs than those who were not regular cannabis smokers,” study author Magdalena Cerdá said in a press release. Cerdá and her colleagues had more bad news to share—cannabis users also had more financial troubles, tended to be more antisocial behavior at work, and experienced more relationship problems.
8. It can triple your risk of death from hypertension
People who smoke weed are typically given the stereotype of being relaxed and chill. But that calm facade may not reflect what’s going on when it comes to blood pressure, says one study from Georgia State University. According to the research, marijuana use was found to triple a person’s risk of death from hypertension (high blood pressure) compared to those who didn’t smoke weed.
9. It could make you more vulnerable to Alzheimer’s
If you want to keep your mind sharp, you might want to lay off the pot. In one 2016 study, researchers found that marijuana users had significantly lower blood flow to the brain than healthy non-smokers. That low blood flow to different parts of the brain, the hippocampus in particular, could put pot smokers at higher risk for cognitive disorders like Alzheimer’s, according to the study.
by Melissa Matthews