Marijuana is often viewed as a remedy for various health issues, but recent scientific findings suggest its effects may be more complex than commonly believed. Researchers at the University of California San Francisco (UCSF) have been examining several myths about marijuana use and its impact on health.
One common belief is that marijuana smoke is less harmful than cigarette smoke. However, Matthew Springer, PhD, professor of cardiology, challenges this idea. “There’s a misconception that marijuana, being more ‘natural’ than highly processed cigarettes from tobacco companies, produces smoke that is less toxic,” says Springer. “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.”
Another myth concerns edibles being 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 that modern cannabis products are much stronger and widely available in forms designed to appeal to consumers.
Edibles can also pose risks because their effects take longer to appear compared to smoking. This delay can lead some users to consume more than intended. Springer explains: “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.”
Long-term health consequences are also under investigation. UCSF research indicates that both smoking and consuming marijuana can affect blood vessels and cardiovascular function. In the CANDIDE study led by Leila Mohammadi, MD, PhD: chronic cannabis smokers showed similar vascular defects as tobacco smokers—including poorly functioning arteries—and even non-smokers who used edibles had arterial problems.
“Using cannabis makes a 30-year-old’s blood vessels resemble those of a 60-year-old,” Mohammadi says.
Concerns extend beyond physical health into brain development—especially for young people whose brains continue maturing until around age 25. William Burrough, MD, MPH notes: “IQ tests are lower in people who use marijuana heavily… 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 there is potential for recovery if use stops or decreases.
Although fatal overdose from marijuana does not occur as with opioids like fentanyl (https://www.cdc.gov/stopoverdose/fentanyl/index.html), high levels of intoxication can still result in severe anxiety or psychosis according to Burrough: “Anyone can be affected by substance use… if you have a family member who has schizophrenia or psychosis it can be particularly risky.”
The notion of self-medicating with marijuana remains controversial due to limited evidence on its effectiveness for conditions such as depression or anxiety; regulation of products varies widely across markets (https://www.fda.gov/news-events/public-health-focus/fda-and-cannabis-research-and-drug-approval-process). Suzaynn Schick, PhD ’01 remarks: “Many people are drawn to marijuana because it’s easily accessible… I hear a lot of magical thinking around marijuana…” Nhung Nguyen PhD PharmD points out difficulties drawing conclusions without standardized regulations.
Springer acknowledges potential benefits in certain medical situations: “Clearly if a cancer patient can’t keep food down… this is what makes them feel better then…that’s a beneficial use.”
Discussing cannabis openly with healthcare providers may help patients make informed decisions about their health needs. Meredith Meacham PhD MPH observes: “They try to have nonjudgmental open-ended conversations…”
Quitting regular cannabis use can present challenges similar to other addictive behaviors such as gambling or social media overuse; withdrawal symptoms may include anxiety or sleep disturbances after stopping daily consumption.
“Many things can be addictive – shopping gambling even social media,” says Burrough. “Addiction happens when you lose control over that thing when it’s impacting your daily life in negative ways… Like many treatment plans in medicine it’s often a combination of options catered to your goals that leads to success.”
