Skip to content

The #1 Cause of Marijuana Side Effects, Say Experts

This ingredient could be distressing or harmful.

Marijuana is no longer the unfairly maligned vice of decades past. Today, more Americans than ever support its legalization and recreational use. Medical marijuana—which is now legal in 36 states—has science-supported benefits. But that doesn't mean pot is completely harmless; no drug is. (Even the most familiar over-the-counter medications like aspirin and ibuprofen have side effects and contraindications.) In some people, marijuana can cause side effects that are unpleasant and even dangerous. This is the main reason why. Read on to find out more—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


The #1 Cause of Marijuana Side Effects

Doctor writing down marijuana research.

Marijuana contains an ingredient called THC, a.k.a. delta-9 tetrahydrocannabinol. It's psychoactive, meaning that it works on the brain. THC is responsible for many of marijuana's most well-known side effects, from relaxation and appetite stimulation (the drug is prescribed to some chronically ill people who have lost their appetite) to some that may be distressing or harmful. Read on to find out more.


Sleep Problems

Sad Woman Lying On Bed

According to research published last month in BMJ, recent marijuana users were 34% more likely to report short sleep duration—less than six hours a night—than non-users. People who used cannabis within the last 30 days were also more likely to oversleep—meaning more than nine hours a night—compared to non-users. Recent marijuana users were also more likely to say they had difficulty falling asleep, staying asleep, or sleeping too much during the past two weeks.  "Current evidence suggests that delta-9 tetrahydrocannabinol (THC), the other major cannabinoid present in most strains of cannabis, has stimulant and hallucinogenic properties contributing to sleep disruption," the study's authors wrote.

RELATED: 5 Recalled Items to Check Your Medicine Cabinet For ASAP


Anxiety and Mental Health Issues

depressed Indian woman holding head in hands, sitting alone on couch at home

A 2019 study published in The Lancet Psychiatry found that daily marijuana users were three times as likely to experience psychosis—losing touch with reality—than non-users. Several previous studies have associated marijuana use with anxiety and depression. "Marijuana should be used with caution if you have a mental health condition," warns the Mayo Clinic. "Marijuana use might worsen manic symptoms in people who have bipolar disorder. If used frequently, marijuana might increase the risk of depression or worsen depression symptoms."

RELATED: This Blood Type Puts You at Risk for Dementia


Heart Problems

man having heart attack

As THC moves from the lungs into the bloodstream, it can increase heart rate and blood pressure, raising the risk of heart attack and stroke. "Marijuana raises heart rate for up to three hours after smoking," says the National Institute on Drug Abuse (NIDA). "This effect may increase the chance of heart attack. Older people and those with heart problems may be at higher risk." One study found that heart attack risk increases up to five times in the first hour after using marijuana.

RELATED: This Makes You 15 Times More Likely to Die of COVID, Says New Study


Cannabinoid Hyperemesis Syndrome (CHS)

young woman with nausea in all denim outfit sitting on bed
Shutterstock / New Africa

Some heavy marijuana users experience severe queasiness, vomiting, and stomach pain. It's called cannabinoid hyperemesis syndrome, or CHS. Experts estimate 2.7 million Americans experience the condition, which is frequently misdiagnosed. Last year, it was the subject of a "Medical Mysteries" column in the Washington Post. One study found that the cannabinoid receptors THC attaches to may cause reduced intestinal motility, or prevent the digestive system from doing its job, leading to nausea and vomiting.

RELATED: How to Reverse a Fatty Liver, Say Experts


Risks to Fetal Development

Female doctor is checking pregnant woman with stethoscope

A recent study conducted by the Proceedings of the National Academy of Sciences found that children of women who use cannabis during pregnancy have a greater risk for developmental and behavioral issues. "Maternal cannabis use is associated with increased cortisol, anxiety, aggression, and hyperactivity in young children," the study's authors wrote. "This corresponded with widespread reductions in immune-related gene expression in the placenta which correlated with anxiety and hyperactivity." Adds NIDA: "With regular use, THC can reach amounts in breast milk that could affect the baby's developing brain." And to get through this pandemic at your healthiest, don't miss these 35 Places You're Most Likely to Catch COVID.

Michael Martin
Michael Martin is a New York City-based writer and editor. Read more about Michael