Anders Gilliand was just 17 years old when he started losing touch with reality.
“He thought there were higher beings communicating with him to tell him what to do or who he was,” said his mother, Kristin Gilliand, who lives in Nashville.
Her son, who had used marijuana since the age of 14, was diagnosed with schizophrenia, a chronic psychiatric disorder that can include symptoms such as delusions, hallucinations and disorganized speech.
He started taking anti-psychotic medication but eventually stopped due to the side effects he experienced. He began using heroin to silence the voices in his head and died of an accidental drug overdose in 2019 at the age of 22.
“If he had never started using marijuana, he might still be here,” said Gilliand, a neuroscientist at Vanderbilt University. Despite a family history of schizophrenia, he believes his son’s marijuana use caused and triggered psychotic episodes.
Anders was among a growing number of young adults, especially men, who are at high risk of developing psychosis due to marijuana use. Evidence from separate studies in Denmark and Britain, among others, suggests a link between heavy cannabis use and psychiatric disorders such as depression, bipolar disorder and schizophrenia. Researchers believe that high levels of THC (the psychoactive ingredient in the cannabis plant that causes high blood pressure) may trigger these disorders in people at genetic risk. THC levels in marijuana have been going strong for decades.
Child psychiatrist Dr., an addiction specialist at the University of Colorado School of Medicine in Denver. “We are definitely seeing an increase in cannabis-induced psychosis among young people,” Christian Thurstone said.
Is high potency marijuana more dangerous?
The stronger the marijuana products, the more likely users are to experience adverse effects, said Nora Volkow, director of the National Institute on Drug Abuse.
“Those who consume the highest doses are at the highest risk of becoming psychotic,” he said.
There is limited research on the adverse effects of high levels of THC, but a European study published in 2020 found that high-potency cannabis products carry an increased risk of hallucinations and delusions compared to low-potency strains.
“There appears to be a relationship between the potency of marijuana and increased risk of psychosis, but more study is needed on this,” said Ziva Cooper, director of the UCLA center for cannabis and cannabinoids.
Research suggests that more than half of people with cannabis-induced psychosis may develop schizophrenia or bipolar disorder.
Young adults and teenagers should be particularly concerned, Thurstone said
“Our studies so far clearly show that the risk of psychosis is dose-related, meaning that the more cannabis exposure is made, especially during adolescence, the greater the risk of developing psychosis, schizophrenia and serious mental illness,” he said.
Another issue with higher-strength products is the potential for developing marijuana use disorder or marijuana addiction. When people are frequently exposed to the stronger aspects of marijuana, they may be more likely to develop marijuana use disorder, but more research is still needed to say for sure.
“There is no longer scientific debate that marijuana can be not only psychologically addictive or habit-forming, but also physically habit-forming,” Thurstone said. “This is a tolerance-producing substance, so people have to use more and more of it to get the same effect.”
According to the Centers for Disease Control, approximately 1 in 10 people who start using marijuana will become addicted..
How might the power of marijuana be linked to psychosis?
Marijuana over-activates high-inducing molecules in our brains known as cannabinoid receptors. When these brain receptors are stimulated, it can cause difficulties in thinking and problem solving and memory impairment.
It is not fully understood how marijuana use can trigger psychosis, but scientists believe it interferes with our brain’s ability to distinguish between what’s going on in our heads and the real world.
“Marijuana in the 60s, 70s, 80s and early 90s was about 2% to 3% THC,” said Thurstone, who has followed the rise of high-potency THC products in smokehouses and dispensaries. “In commercialized products today, these rates are routinely over 20 percent, about 10 times stronger.”
Patrick Johnson, assistant store manager at Frost Exotic dispensary in Colorado, has been in the cannabis industry since 2009 and has seen firsthand the growth in pot’s potency. After marijuana became legal for recreational use in Colorado in 2014, THC levels really started to rise, Johnson said.
Since then, 24 states, two territories, and Washington DC have legalized the medical and recreational use of marijuana.
Experts say consumer demand for more potent weed is increasing as the number of people using weed legally increases across the country.
“After the fun [legalization] I personally saw it go from 19 or 20 percent to 30 or 35 percent,” Johnson said.
They currently carry strains as low as 14% to 30% in his shop. Johnson said most customers prefer the strong stuff.
Mahmoud ElSohly, a professor of pharmacy and cannabis researcher at the University of Mississippi, said one reason the effects of marijuana products have become stronger over the years is that customers can develop tolerance to the drug. It studies this issue in collaboration with the National Institute on Drug Abuse and finds that average potency increased from 3% to 15% from 1995 to 2021.
“People continue to need increasingly higher potency products to get the high they are looking for,” he said.
ElSohly has said in the past that a compound containing 2% THC could be enough to get most people high. With more intense use, many people have now built up a tolerance and may need to smoke multiple joints with 2% THC or purchase a single joint with 6% to get a similar feeling.
Is one type of marijuana safer?
The potency of marijuana primarily refers to the THC content in the marijuana flower or bud, which is the smokable part of the plant.
THC levels in flowers can be close to 40%, while other products such as concentrates or oils can contain amounts as high as 95%.
The problem is that there isn’t yet a widely accepted standard dose like there is for alcohol, so it can be difficult to predict how someone will respond to different marijuana products, UCLA’s Cooper said.
It is also difficult to develop unit doses for inhaled flammable products. A typical joint may contain between 100 and 200 milligrams of THC, but that doesn’t tell the whole story, Cooper said.
How much THC a marijuana smoker is exposed to can vary. How long and how deeply do they breathe? Or how long do they wait between puffs because too much THC is lost in the “sidestream” smoke from the burning end of the joint between hits?
By comparison, marijuana edibles like gummies, cookies, and brownies generally contain 5 to 10 milligrams per dose. There is a movement towards creating unit doses for edibles and limiting how much THC can be consumed at one time. For example, in New York state, the number is 10 mg per serving.
How high can THC go?
“I don’t think there could be much more of an increase,” said Volkow, of the National Institute on Drug Abuse. “Sometimes there can be a level where too much can become aversive and people smoke and become very agitated or paranoid.”
He is optimistic that current marijuana flower’s THC levels will not increase to 50%.
Cooper said there is a limit to the amount of THC the plant can produce, although manufacturers are finding clever ways to increase the chemical.
“The industry is adding more THC to plant products,” he said, including infusing pre-rolled hemp cigarettes with additional THC. “We’re starting to see people being exposed to THC at levels we haven’t seen in the past.
This article first appeared on NBCNews.com.