Cannabis: As Drug Becomes More Mainstream, Experts Sound the Alarm About its Dangers
By Jaimie Seaton
Ask a room full of people if cannabis is safe or addictive, medically helpful or harmful, and you’ll get myriad answers. Some will swear medical marijuana is the only thing that relieves their pain, some will say all cannabis is unsafe and others will say they smoke pot recreationally and don’t see a problem. Still others—including medical clinicians and social workers—might confess that they don’t know much about it.
One reason is that there is limited research into cannabis, despite the fact that, according to the latest government statistics, cannabis is the most commonly used illicit drug in the U.S., and in 2023, nearly one in four adults 18 and over reported using it. Even with this dearth of research, one 2024 survey found that 80% of those who have tried marijuana and 58% of Americans overall believe that it is very or somewhat safe to use. Pew research from 2024 found that 88% of Americans believe marijuana should be legal for medical or recreational use.
As the country moves toward legalizing cannabis on a federal level, social workers and other experts are issuing a wake-up call about its potential dangers. From teenagers to octogenarians, people across the country are struggling with addiction and other serious physical and mental health issues associated with marijuana use. While some experts believe cannabis has legitimate health benefits when used under the right conditions, they also say using cannabis does not come without risk—and they advocate for more research into the short- and long-term effects of its sustained use. To this end, some argue that legalizing cannabis nationally would allow it to be regulated, making it safer and easier to study.
Legal Status
Cannabis is legal for medical use in 38 states, and 24 of them—plus Washington, D.C.—have legalized recreational use. At the federal level, it’s classified as a Schedule I drug—which has no accepted medical use and a high potential for abuse—meaning that cannabis sits alongside drugs such as heroin and LSD. In 2022, President Joe Biden officially requested that cannabis be reclassified as a Schedule III drug, which are substances or chemicals that have a moderate to low potential for physical and psychological dependence but still have medical uses. If the reclassification is successful, it might be a step on the road to federal decriminalization or legalization.
Much of the argument for decriminalizing or legalizing cannabis at both state and federal levels has centered on the fact that marginalized people are disproportionately incarcerated for using it. One study found that Black people are nearly four times more likely than white people to be arrested for marijuana use. “We’ve approached decriminalization as a priority item,” says Mel Wilson, LCSW, a senior policy advisor to NASW. And while decriminalization is clearly a social justice issue, Wilson emphasizes that NASW approaches it from a public health perspective.
Citing the need for social workers and others to address the misuse, overuse and harmful physical and psychological effects of cannabis, he says decriminalization should be seen as a public health intervention rather than a criminal one. Wilson adds that he personally believes legal cannabis products should have warning labels about possible side effects.
What Is Cannabis and How Many People are Using It?
Cannabis refers to seeds, stems, flowers and dried leaves from cannabis sativa or cannabis indica plants. Marijuana is a psychoactive drug that comes from the cannabis plant and contains THC, along with nearly 500 other chemicals. THC, a mind-altering compound that can cause harmful health effects, is what causes users to feel “high.” (Note: This article focuses on marijuana and does not include CBD products derived from hemp, which by definition contain less than 0.3% THC.)
People also smoke or eat different forms of marijuana extracts, which can deliver a larger amount of THC faster and are potentially more dangerous because they may contain additives or be contaminated with other harmful substances. One method that is on the rise is smoking THC-rich resins extracted from the marijuana plant. Referred to as “dabbing,” this method can deliver dangerously high levels of THC and can cause short- and long-term mental and physical health effects.
Not every person who uses cannabis will become addicted or suffer other serious effects, but any level of cannabis use can be harmful to one’s health—and a lot of people are using it. According to the Substance Abuse and Mental Health Services Administration (SAMHSA)’s 2023 National Survey on Drug Use and Health, the percentage of cannabis users was highest among young adults ages 18 to 25 (36.5% or 12.4 million people), followed by adults ages 26 or older (20.8% or 46.5 million people), then by adolescents ages 12 to 17 (11.2% or 2.9 million people). A separate poll conducted by Gallup found that cannabis use is highest among less educated and lower-income adults.
“It is worth noting that data from the CDC’s Youth Risk Behavioral Survey as well as the NIH-funded Monitoring the Future Survey show that cannabis use among U.S. high school students is down over the last two decades,” says Capt. Christopher Jones, director of the Center for Substance Abuse Prevention at SAMHSA.
Despite the decrease, 19.2 million people in the U.S. in 2023 had a past-year cannabis use disorder (CUD) — including 1.2 million people ages 12-17 and 17.9 million ages 18 or older, according to SAMHSA. Its data shows that one in 10 of those who use cannabis may become addicted; for those who start before age 18, the rate of addiction rises to one in six. Chronic, heavy use of cannabis products with THC can lead to CUD. Some studies estimate that 22% to 30% of people who use cannabis have CUD.
The Risks of Using Cannabis
The THC levels in today’s cannabis are significantly higher than in previous decades. In 1995, the THC level of cannabis seized by the Drug Enforcement Administration (DEA) was 3.96%. By 2022, the level had reached 16.14%. This can increase the risks to users. Unintentional poisoning of children with edibles is also a risk and can lead to serious illness and hospitalization. Dabs, oils and edibles can have THC levels up to 90%, producing a more intense and longer-lasting effect than with smoking.
Drew Rangel, CSWA, MSW, a substance use disorder counselor at Hazelden Betty Ford Foundation, says he’s seeing people who previously may not have used cannabis trying it, taking a gummy for instance, because they were told it would relieve pain.
“They don’t realize the potency or what they’re really dealing with. I’m seeing more people with cannabis use disorder than I think I’ve seen historically in an adult population,” Rangel says, adding that most of his patients are between 30 and 65 years old.
He believes part of the reason for the uptick is that cannabis is legal for recreational and medical use in Oregon, where he practices. “In the Portland metro area, there’s a dispensary on every corner … It’s really everywhere and that’s significant,” Rangel says.
Hazelden Betty Ford currently does not accept Medicare or Medicaid, so the patients all have health insurance or pay out of pocket. Other than that common denominator, Rangel says his patients are a cross-section of society—from construction and transportation laborers to health care workers, corporate executives and even airline pilots.
While some people may seek help at the urging of friends and family or on their own, many are mandated to seek treatment from their employers or the courts. Rangel says CUD often is a secondary diagnosis to alcohol or another substance use disorder, which can make it difficult to treat. With some patients, even if they recognize that they must give up alcohol or other substances, they don’t see their cannabis use as a problem or don’t believe they’ll be able to deal with their chronic pain without it.
Hazelden’s program is abstinence-based, and Rangel points out that it takes at least two years for the brain to recover. There also are advocates of a harm-reduction approach to addiction. One 2022 study found that about half of Americans who self-identify as having recovered from an alcohol or other drug (AOD) problem continue to use cannabis in some form. The study concluded that while abstinence is not required to overcome an AOD problem, it leads to greater functioning.
Addiction Isn’t the Only Risk
Even for users who don’t become addicted, cannabis is far from benign. It can cause numerous health issues, including risks to the pulmonary, cardiovascular and endocrine systems, and can impair function in everyday activities, such as driving.
Cannabis use directly affects brain function. Developing brains, like those in babies, children and teenagers, are especially susceptible to the harmful effects of cannabis and THC because the brain continues to develop until about age 25.
Marijuana, which is the most widely used illicit drug among pregnant women in the U.S., poses serious, sometimes fatal risks to fetuses and babies. THC and other chemicals also can be passed to the baby during breastfeeding, increasing the risk of impairment to the baby’s brain development.
Cannabis can interact negatively with prescribed medications, posing a particular risk to seniors, who often take numerous prescribed medications.
Those who use cannabis at least once a week and adults who started using in their adolescent years are more at risk for cannabinoid hyperemesis syndrome, which causes severe nausea and vomiting.
Because of the patchwork legal status of cannabis across the country—and the fact that the FDA doesn’t regulate it—the product being used could contain other harmful substances.
Marijuana and Mental Health
In addition to negatively affecting cognitive function, cannabis use also can pose a risk to mental health. “There’s robust evidence that, for people who use a lot of cannabis early, it increases their risk for developing symptoms of psychosis and psychotic disorders,” says Ryan Petros, PhD, LCSW, an associate professor at the School of Social Work at the University of Washington.
Cannabis use is particularly harmful to young adults (adolescence to mid-20s) with existing psychotic disorders—whose use of cannabis is staggeringly high. Petros says that 60% to 80% have used cannabis at some point in their lifetime. Along with the correlation of cannabis use and the development of psychotic disorders, some hypothesize that those with existing psychotic disorders use cannabis as a coping mechanism.
In 2023, Petros and colleagues Denise Walker and Maria Monroe-DeVita published a scoping review on motivations for cannabis use among young adults with active psychotic disorders. Petros says some people may use the drug to help with psychosis, dysphoria related to a psychotic disorder or anxiety, “but as a general rule, people are not typically using cannabis to decrease their psychotic symptoms. They’re using it for other reasons: just to have fun, maybe to engage in social activities, maybe because they’re bored.” He adds that people with schizophrenia have a high propensity for boredom.
One challenge among cannabis users, and particularly young adults, is a lack of knowledge about the substance. They’ve heard that THC has health benefits, “but people don’t necessarily have access to the research about it, and they don’t hear that much about the risks,” Petros says. He says when hard data about rehospitalization treatment and dropout rates is shared with young people in treatment, it’s often new information. “There can be this sense of, ‘well, why didn’t anybody tell me? if I knew that I wouldn’t have done it.’ But that information isn’t widely available.”
One of the scoping review’s findings is that there is no evidence-based practice that’s been identified to reduce cannabis use among those with psychotic disorders, and the trio is currently conducting a pilot program on new interventions. When asked what they want out of an intervention, the subjects uniformly said they want a nonjudgmental approach.
“They want an opportunity to talk about [their cannabis use] and they want an opportunity to learn some of the research,” Petros says. “So the intervention that we’re optimizing and trialing right now is a motivational enhancement therapy approach, which combines science-based information with motivational interviewing. And so far, our pilot information says that it seems to be the way to go."
Not Your Grandmother’s Marijuana
Older Americans, some of whom have smoked marijuana intermittently since youth and some who started later in life, are turning to cannabis to self-medicate for various health issues. However, as noted, the marijuana of the 1960s, ’70s and ’80s was far less potent than today’s marijuana, so many older users experience adverse health effects.
Allison Moore, MD, MPH, FACP, AGSF, a public health researcher whose work principally focuses on older adults with unhealthy substance use, says cannabis use among people 50+ is growing—and she believes it’s underreported because it’s classified with heroin and other more serious drugs—often with serious health consequences. She explains that seniors often don’t discuss their use with their doctor because of stigma and legal status in their state.
“The biggest barrier I’d say to older adults or patients asking their doctors questions is that … many of us just have no clue about it, so we really can’t advise,” Moore says, citing the lack of research into the therapeutic uses and dosing of cannabis.
Seniors use cannabis for insomnia, pain, mental health issues or just to relax, Moore says, and they are more at risk from harm simply because people’s bodies react to medications and substances differently as we age. Compounding the problem is that they’re not sure of the dose or how to use the product.
“For example, gummies take anywhere from 30 minutes to two hours to kick in. So the problem has been that people take a gummy, don’t feel any effect trying to get to sleep, take another, don’t feel anything again, and then they can overdose on it because they haven’t waited the requisite time to have it really work,” Moore says. “By that time, they feel agitated, confused and sometimes, I think, paranoid.”
Even without overdosing, Moore says seniors are extremely likely to experience dizziness (which can lead to falls), as well as hypertension, fast heart rate, cardiovascular disease and nausea. If they smoke cannabis, they can have serious respiratory issues, particularly if they have underlying conditions such as chronic obstructive pulmonary disease, or COPD.
Moore says it’s important for health care workers to ask their senior patients about all the medications and cannabis products they’re using, as the interactions can be dangerous. “If they’re taking opioids and they’re using cannabis, or they’re taking even over-the-counter or prescription sleeping meds and taking cannabis, that can be trouble,” she says.
While noting that cannabis has many well-established downsides, Moore says there is research to support potential health benefits of cannabis products. In her own practice, she will advise patients to use a cannabis product for medicinal purposes, though she’s quick to note that she also advises them what licensed dispensary to use and the exact dosing.
“I think we need to learn a ton more to really truly comfortably advise patients. So many physicians are just like, ‘I don’t want to go there.’ But the problem is the patients have already gone there, so it’s sort of a harm-reduction approach where you want to make sure they aren’t doing things that really could hurt them.”
Jaimie Seaton is a New England-based journalist with 30 years of experience. Her work appears in multiple publications, including Scientific American and Smithsonian Magazine.