Marijuana is often discussed as a potential remedy for various health issues, but experts caution that its effects on the body are complex and sometimes misunderstood. Researchers at the University of California, San Francisco (UCSF) have addressed several common myths about marijuana use.
One misconception is that marijuana smoke is less harmful than cigarette smoke. Matthew Springer, PhD, professor of cardiology, explains: “There’s a misconception that marijuana, being more ‘natural’ than highly processed cigarettes from tobacco companies, produces smoke that is less toxic. But that’s not the case. It’s nasty stuff, with benzene, formaldehyde, and heavy metals you don’t want to be exposed to, among many other substances.” UCSF experts note that inhaling any kind of smoke can contribute to cardiovascular disease or worsen respiratory conditions such as asthma.
Another belief is that edibles are safer than smoking marijuana. Laura Schmidt, PhD, MSW, MPH, professor of health policy studies at UCSF states: “There’s a mythology, popularized by the comedians Cheech and Chong in the 1970s, that marijuana is a benign product that doesn’t cause significant intoxication. That’s unrealistic today, with commercialized cannabis.” She adds: “We’ve never had cannabis this potent or abundant. We’ve never had cannabis commercialized or packaged like food. Many cannabis edible products mimic junk food. Bright colors, cartoon characters. They’ll just change the name: Molly Ranchers versus Jolly Ranchers.”
Edibles can also lead to unintentional overconsumption because their effects take longer to appear compared to smoking. Springer notes: “Someone will take an edible and five minutes later they’ll say, ‘I don’t feel it – I’m going to take more,’ and end up taking way too much. They rush to the emergency room with panic, palpitations, and nonstop vomiting.”
Research also indicates long-term health risks associated with marijuana use. Leila Mohammadi, MD, PhD led UCSF’s CANDIDE study which found chronic cannabis smokers exhibited similar vascular dysfunction as chronic tobacco smokers—including poorly functioning arteries and blood serum inhibiting important properties of endothelial cells lining blood vessels. Endothelial dysfunction signals early risk for conditions like hypertension and atherosclerosis.
The study also found people who consumed only edibles experienced arterial problems; however their blood did not cause identical damage in lab-grown endothelial cells—suggesting different impacts between smoked and ingested forms.
“Using cannabis makes a 30-year-old’s blood vessels resemble those of a 60-year-old,” Mohammadi says.
Young people may believe they are immune from harm due to age; however William Burrough, MD, MPH assistant professor of pediatrics at UCSF points out brain development continues until about age 25: “IQ tests are lower in people who use marijuana heavily particularly during adolescence. Studies using brain scans have shown teenagers who frequently use cannabis have reduced brain matter and activity in the areas crucial for decision making and planning.” He adds stopping or reducing use can allow for recovery since “the body’s ability to heal is remarkable.”
While fatal overdose from marijuana does not occur as it does with opioids like fentanyl [https://www.cdc.gov/drugoverdose/deaths/index.html], users can still experience severe intoxication including anxiety or psychosis according to Burrough: “Anyone can be affected by substance use but if you have a family member who has schizophrenia or psychosis it can be particularly risky.”
Some turn to marijuana for self-medication due its accessibility; Suzaynn Schick PhD ’01 associate professor at UCSF observes: “Many people are drawn to marijuana because it’s easily accessible… I hear a lot of magical thinking around marijuana often from people who feel they don’t have better safer alternatives.” Nhung Nguyen PhD PharmD notes there remains insufficient evidence regarding benefits for mental health due largely to lack of standardized regulation.
Springer acknowledges some medical benefit in certain situations such as cancer patients unable to tolerate oral medications: “Clearly if a cancer patient can’t keep food down… this is what makes them feel better then…that’s a beneficial use.”
Burrough emphasizes balanced discussion about risks and benefits: “These conversations get so caught up in people’s personal feelings… Maybe cannabis isn’t as harmful as some other potential substances… At the same time using it too often can lead to real harm.”
Discussing marijuana openly with healthcare providers may help address concerns; Meredith Meacham PhD MPH assistant professor at UCSF says clinicians aim for nonjudgmental dialogue asking questions like “‘Is it OK if we talk about cannabis? Tell me about your use.’”
For those considering quitting daily use withdrawal symptoms such as anxiety sleep disruption or appetite loss may signal dependence requiring professional support through behavioral therapies medication or interventions addressing underlying issues.
“Many things can be addictive – shopping gambling even social media,” Burrough says.“Addiction happens when you lose control over that thing when it’s impacting your daily life in negative ways…the good news is there are ways we can help…”
