With marijuana at a new level of scrutiny, here’s what the research says

“Illinois Democrats legalized marijuana,” proclaims a new billboard in Chicago. The ad, paid for by Gov. JB Pritzker’s campaign fund, takes credit for a change that polls show is supported by about two-thirds of Americans.

Chicagoan Sheila Hogan, one of 140,000 people registered in the state to use medical cannabis, believes in its powers. She uses mild gummies at bedtime to relieve debilitating pain from spinal stenosis, which has allowed her to get back to gardening and pickleball.

“I could not even believe it,” she said. “It was remarkable. I was able to get a lot more active.”

Despite support for legalization, and increasing use of marijuana nationwide, a recent Gallup poll showed slim majorities say it negatively affects both society and most people who use it — but is still less harmful than tobacco and alcohol.

The evolving perceptions of cannabis come as major changes are afoot in the regulation of the drug.

The Biden administration has proposed reclassifying pot as less-dangerous, making it legal with a prescription. Democratic presidential candidate Kamala Harris has called for decriminalization, while Republican candidate Donald Trump, who legalized hemp, has said he is open to decriminalization, and that legalization should be up to the states.

At the state level, more jurisdictions continue to legalize weed. Ohio became the most recent state to do so, effective this year. Residents of Florida and North and South Dakota will vote on the issue Nov. 5. So far, 24 states — with a majority of the nation’s population — have legalized marijuana for adults, and most states allow some level of medical use.

So with the nation at a potential tipping point in its treatment of cannabis, what have we learned from legalization, and what does the latest research show about its effects?

First, the sky has not fallen in those states that legalized. A report by the Cato Institute in 2021 concluded that the effects, both pro and con, were fairly limited.

Advocates have suggested that legalization reduces crime, improves public health and stimulates the economy. Critics argued that legalization spurs marijuana and other drug use, increases crime, harms public health and hurts kids in school.

But many of these claims, Cato reported, were overstated and sometimes baseless.

While adult use of marijuana is at record highs nationally, use among teens has not risen appreciably in states that have legalized it, surveys have found. In Illinois, the legal age to purchase marijuana is 21.

As far as crime goes, homicides and other violent crimes increased significantly in Illinois since recreational legalization in 2020, before decreasing substantially recently. That was part of a nationwide trend that criminologists say was influenced by many factors, including civil unrest and the COVID pandemic. In a prior study, the Cato report found no substantial increase or decrease in violent crime through 2018 in states that legalized.

Traffic fatality rates also surged in Illinois in 2020 and 2021, before falling in 2022, again part of a nationwide trend fueled by the pandemic. A 2022 study found a 6% increase in injury crashes and a 4% increase in fatal crash rates in states after legalization.

Ingestion of edibles by toddlers and overdoses by adults also have increased in Illinois since legalization, but remain far fewer and less harmful than overdoses of other substances.

One significant economic effect has been that legal weed has generated substantial tax revenues — about $1 billion since 2020 for Illinois.

After administrative expenses, 25% of that money goes to community reinvestment; 20% for substance abuse prevention and mental health treatment; 8% to local governments for law enforcement; and 45% to the state budget. Illinois has awarded $244 million for community programs from weed tax revenue.

Despite widespread claims about the effectiveness of using pot to treat a host of medical conditions, the evidence is limited.

After a comprehensive review of medical uses last year, Health and Human Services found support for the use of marijuana for three conditions: anorexia related to a medical condition; nausea and vomiting; and pain, especially nerve pain.

Those findings match with prior Food and Drug Administration approval of synthetically derived THC, known as dronabinol, for the treatment of nausea, vomiting and anorexia. The agency also has approved pure CBD, under the brand name Epidiolex, to treat a rare form of severe epilepsy.

But marijuana showed mixed or inconclusive effectiveness for anxiety, inflammatory bowel disease, and post-traumatic stress disorder.

Anxiety disorder is a good example of divided views of cannabis. Though it’s one of the most common reasons people use the drug, the Illinois Medical Cannabis Advisory Board recently failed to recommend it as a qualifying condition on a tie vote.

Board member and family nurse practitioner Katie Sullivan said that with guidance, high doses of CBD, a nonpsychoactive component of pot, with low amounts of THC — the part of pot that gets users high — can help some people with anxiety.

But a study of 12,000 patients showed it’s not very helpful for many and can cause shrinkage in parts of the brain, neurologist Amarish Dave cautioned.

“There’s real risk,” he said. “There are studies to suggest it can make it worse for a significant portion of people.”

With people in Illinois able to buy cannabis for any reason, they may be using it for anxiety without any medical guidance. Board members agreed that Illinois needs better education of doctors and the public on the medical use of cannabis.

One of the advantages of marijuana is that it doesn’t have some of the side effects of opioids, such as constipation, or of causing fatal overdose. Many people use low doses occasionally without incident.

But modern commercial marijuana is much more potent than street weed of the past. It can have mild to moderate adverse effects, such as causing anxiety or, in rare cases, psychotic episodes.

More alarming, a National Institute on Drug Abuse study found that young men with cannabis dependence were at a significantly increased risk of developing schizophrenia.

And smoking or vaping can damage the lungs. One study showed that cannabis use was tied to increased risk of severe COVID-19.

The most popular nonpsychoactive component of cannabis, CBD, is generally well-tolerated by users, without the anxiety or other side effects of THC. It has been shown to help people with certain severe forms of epilepsy, though in high doses it could cause anemia, flatulence and sleepiness.

One small study at the University of Colorado suggested CBD was associated improvements in cognition and emotional issues associated with Parkinson’s disease. Other studies have suggested potential benefits for ulcerative colitis, opioid withdrawal and sleep, but doctors say much more research is needed to prove widespread health claims.

Last year, at the request of President Joe Biden, the U.S. Department of Health and Human Services and National Institute on Drug Abuse recommended rescheduling marijuana from Schedule 1 (the highest) to Schedule 3 on a scale of 5 that rates controlled substances by their dangers and medical effectiveness.

Currently, at the federal level, marijuana is classified as having no medical use and high risk for abuse and addiction — somehow more so than even fentanyl or methamphetamine, which, unlike marijuana, kill thousands of people every year.

Instead, pot would be categorized as having a moderate to low likelihood of dependence and would be legal for medical use with a prescription. It would allow increased research and would let marijuana businesses take federal business tax deductions, making it easier to make money. Consumers would likely see little direct effect, since state law would still control where and how pot is legal.

At the local level, one aspect of the Illinois medical program upsets both patients and doctors.

Cannabis patients in the state still are restricted to getting their medical products without tax at the 55 original designated medical dispensaries. Some of those companies, which have a captive market, have lobbied to keep it that way.

Dr. Leslie Mendoza Temple, a member of the state cannabis advisory board, said the state should allow patients to get their medicine at any recreational dispensary.

“The consistency of supply for our medical patients has always been an issue,” she said. “It reduces compliance and confidence in the program. Our medical patients who built this program are being edged out by market forces.”

rmccoppin@chicagotribune.com