Flanked by a handful of protesters outside a Timonium medical cannabis dispensary on Saturday afternoon, neuroscientist Dr. Christine Miller raised a sign with a bolded bullet-point list of “the social costs of cannabis.”

Poor academic performance, it said — and psychotic symptoms; cardiac problems such as stroke or arrhythmia; depression and suicidal behavior.

Miller, a Towson resident and former Johns Hopkins University researcher, organized the protest to urge passersby to vote against a Nov. 8 referendum to legalize adult-use recreational cannabis in Maryland.

While polls show broad support for the measure, Miller and other critics say there’s been little focus on mental health harms that marijuana, which is already approved for medical use, may cause or exacerbate, including psychosis, schizophrenia and depression, especially in children and teenagers.

“You read the rationale for legalization — which I do think will pass in the fall — and so much of it is false information and biased information and lacks a lot of scientific rigor,” said another demonstrator, Kevin Becker, a retired geneticist who worked for three decades at the National Institutes of Health.

“The public discussion about cannabis centers on social justice issues and tax revenue,” added Becker, who lives in Sparks Glencoe. “They have completely ignored or minimized the public health component.”

The referendum was triggered by the Maryland General Assembly’s decision earlier this year to let voters decide whether adult-use recreational marijuana and possession will become legal for those age 21 or older. If passed, the amendment would become state law on July 1, 2023.

Polling shows that support for legalizing recreational use of marijuana has grown. Fifty-nine percent of Marylanders said they support legalization, according to a September poll conducted by Goucher College in partnership with The Baltimore Banner and WYPR radio. That’s up from about half of voters who backed such a measure in 2014.

The poll found 34% of Marylanders were opposed and 7% undecided.

President Joe Biden on Thursday announced a sweeping pardon for all prior federal simple possession of marijuana offenses and tasked federal officials with reviewing the drug’s controlled substance classification.

“Not only will thousands of lives be improved by removing this burden, but it also sends a powerful message to states that it is time to end prohibition and give people the tools they need to live full productive lives without the shackles of the criminal justice system,” said Toi Hutchinson, president and CEO of the Marijuana Policy Project, in a statement last week.

But the legalization campaign in Maryland worries skeptics such as Mark Marchione, a northern Baltimore County resident who said his son’s mental health and sense of reality eroded after chronic cannabis use.

Tetrahydrocannabinol, the main psychoactive compound in most cannabis products, “is a drug,” Marchione said.

“The problem with it is that it can cause mental health problems,” he said. “The thing I’m most concerned about is young people.”

Maryland lawmakers legalized cannabis for medical use in 2014, allowing limited numbers of cannabis producers and dispensaries to operate. Many studies show the drug may be beneficial for its inflammatory properties and in treating nausea, pain and sleep problems.

But many doctors say not enough is known about medical marijuana to understand how and when to recommend it. Some physicians have resisted — and two hospital systems forbade their nurses and doctors from — registering with the state to write patient referrals for cannabis as medical treatment.

A peer-reviewed study by Johns Hopkins Medicine published online in 2020 found cannabis users “reported less pain, better sleep and reduced anxiety, along with taking fewer prescription medications,” and were less likely to have visited an emergency room or to be admitted to a hospital than people who didn’t use cannabis for medical purposes.

The researchers surmised that “more funding and clinical trials are urgently needed to determine what conditions the drug may treat.”

But Becker, who has written a book on the subject but clarifies that he’s not a cannabis researcher, said there’s a wide body of research on the effects of cannabis and that the evidence “is very strong.”

He and Miller acknowledge that cannabidiol, which is derived from the hemp plant but isn’t psychoactive, has shown demonstrable benefits. But they cite findings from studies that concur with information from the World Health Organization, which says that “heavy use of cannabis is associated with an elevated risk” of psychotic disorders.

Some clinical research suggests that the use of cannabis products containing potent levels of THC induces cannabis-associated psychotic symptoms such as paranoia and hallucinations. Several studies suggest that people who experience cannabis-induced psychosis are at high risk of developing a long-term psychotic disorder.

Marchione said his son began using cannabis regularly when he was 16. Despite having no known family history of schizophrenia or mental health issues, Marchione said, his son began to experience auditory hallucinations and believed he was “being manipulated by outside forces.”

Marchione said his son dropped out of college and the family sought treatment.

“When someone is psychotic, there’s not one thing you can say to them that will convince them [what they’re experiencing] is not true,” Marchione said he was told by a mental health professional. The only effective treatment is prescription medicine, they said.

But it wasn’t until Marchione’s son was ordered by a court to receive treatment for psychosis symptoms that he was able to get prescription medications, Marchione said. He continues to take them.

“The problem is that marijuana today is much more powerful than it used to be,” Marchione said.

“The human brain is still developing” when many teenagers and young adults “start experimenting” with cannabis, he said.

Becker and Miller said that if prohibition of the drug is ended, they want at least to see state health officials make an effort to educate the public on possible side effects of cannabis use. They also want Maryland regulators to prioritize public health warnings on cannabis products.

Warning labels are slapped on cigarette packs, alcoholic products and every advertisement about pharmaceutical drugs, Becker said.

“If you get psychotic and you get chronic depression that leads to suicide … it’s tragic,” he continued. “We should have warning labels about that. People can make rational decisions.”

taylor.deville@thebaltimorebanner.com