Is marijuana dangerous? It is a question millions of people are asking as legalisation spreads across the US and beyond. According to one physician who has spent years tracking the science on cannabis, the latest research leaves very little room for doubt.

Dr Raymond Wiggins, an oral surgeon and author of Weeding Out the Myths About Marijuana, recently spoke with CBN News about the wave of studies that has emerged since his book was published in mid-2024. After searching PubMed for cannabis research published in 2024 and 2025, Wiggins found over 6,500 results. He narrowed that pool to the largest and most methodologically rigorous papers, around 300 in total, including multi-centre studies involving millions of participants and systematic reviews that pool data across many earlier trials.

“It’s kind of like going from standard definition TV to 4K or 8K in a very short period of time,” Wiggins said. “The data is much stronger. It’s much more reliable.”

What that data reveals about marijuana health risks should, he argues, be prompting a very different public debate.

“Marijuana Does Kill”

One of the most persistent myths surrounding cannabis is that, unlike opioids or alcohol, it does not cause death. Wiggins pushes back on this directly.

“We had tons of studies already that show that marijuana does kill,” he said. “It doesn’t kill in the same way that opioids do. It generally doesn’t kill directly like opioids, but what it does is it kills through heart attacks and cardiovascular disease, it kills through suicide, through auto accidents, through violence, and much more.”

Recent studies have sharpened those numbers considerably. Several papers published in the past 18 months show a one-and-a-half to two-and-a-half times increased risk of all-cause mortality among marijuana users compared to non-users. For those who develop cannabis use disorder, that risk rises to three times.

On the roads, the picture is similarly alarming. Multiple new studies confirm that marijuana impairs driving performance, with one finding a 55% increase in fatal auto accidents and a twofold increase in injury accidents among THC users. What is particularly troubling, Wiggins said, is that the impairment does not end when the high does.

“These issues don’t fully resolve in people who are chronic users or people who started young. So many marijuana users don’t drive safely even when they’re not high.”

One study also found that CBD, widely regarded as the benign counterpart to THC, impairs lane-keeping ability as well.

The Heart, the Lungs, and the Blood Vessels

For anyone still asking whether marijuana is dangerous, the cardiovascular evidence alone makes for sobering reading. In March this year, the American College of Cardiology published findings drawn from a study of approximately nine million people. Among individuals under the age of 50 with no significant prior cardiovascular history, marijuana use was linked to a sixfold increase in heart attack risk, a fourfold increase in ischaemic stroke, a doubled risk of heart failure, and an eightfold increase in the risk of dying from a heart attack.

A separate study published in JAMA Cardiology found that regular marijuana users had blood vessel damage and reduced vascular function comparable to tobacco users, and in some respects worse. Critically, those effects were present not only in people who smoked cannabis but in those who consumed edibles. Overall vascular function was reduced by roughly half compared to non-users.

On the lungs, new research has confirmed a 31% increase in asthma risk, alongside already-established links to bronchitis, generalised lung inflammation, and a sixfold increase in lung cancer risk.

Mental Health: The Numbers Are Getting Worse

Among the most significant marijuana health risks documented in recent research are the psychiatric ones, and Wiggins notes the figures are climbing in part because the potency of cannabis products has risen so sharply.

“As the potency goes up, we’re seeing these numbers go up.”

A major study found a threefold increased risk of schizophrenia among all marijuana users, rising to six times in adolescents. Among those with cannabis use disorder specifically, the risk was 15 times higher than in non-users. The same research found that schizophrenia linked to cannabis use disorder is three times more common in US states with liberalised marijuana laws.

A 2024 study focussing on adolescents aged 12 to 19 found an 11-fold risk of psychosis compared to non-users. For those who had previously been hospitalised or visited an emergency department because of marijuana use, that figure climbed to 27 times.

In early 2025, a study of over nine million people found a 16-fold risk of depressive episodes among regular marijuana smokers. Research also consistently confirms a two- to three-fold increased risk of suicidal ideation and suicide attempts among users.

Other documented effects include anhedonia, a diminished capacity to feel pleasure, a 75% increase in paranoia, a twofold increase in anxiety, and a strong association with personality disorders.

“When I talk with families, I hear that all the time,” Wiggins said. “My child’s, or my loved one’s, personality is way different since they’ve been using marijuana.”

Pregnancy, Diabetes, and Obesity

The question of whether marijuana is dangerous extends into areas that have received far less public attention. New studies have found a meaningful correlation between cannabis use during pregnancy and autism spectrum disorder. Other research shows a fourfold increased risk of diabetes among marijuana users and a sixfold increased risk of obesity, figures Wiggins describes as covering “brand new topics that we really didn’t know a lot about in the past.”

On the obesity finding, the mechanism is not straightforward. Cannabis typically suppresses motivation and increases appetite, which leads to weight gain in the majority of users. In cases of severe addiction, however, the opposite can occur as individuals disengage from basic daily activities including eating.

Why Is Marijuana Dangerous Evidence Being Ignored

With over 6,500 studies published in roughly 18 months, the question of why public policy has not shifted accordingly is a pointed one. Wiggins is direct about the answer.

“I think there’s no doubt that it’s for one reason. It’s for the money.”

He points to an industry publication that cited just 15 studies suggesting marijuana posed minimal risks, cherry-picked from a pool of 6,500. Political donations from cannabis industry interests have, in his view, shaped the votes of legislators who might otherwise act on the evidence.

Wiggins is currently co-writing a second book aimed specifically at parents, alongside a former state representative who witnessed firsthand how industry money influenced policy and who began receiving letters from families whose children had been harmed or killed as a result of cannabis use.

The research, he says, is no longer ambiguous. Is marijuana dangerous? The science has answered that question. The challenge now is making sure the public hears the answer.

Dr Raymond Wiggins’s book, Weeding Out the Myths About Marijuana, is available now on Amazon. The expanded edition includes additional material on the spiritual dimensions of addiction and recovery.

Source: CBN