States where the use of marijuana has been legalized, have not taken any steps to limit the potency of marijuana — and the result has been that the potency of cannabis has increased dramatically over the past several years.
The potency of marijuana depends on the amount of delta-9-tetrahydrocannabinol or THC, the main intoxicant in cannabis that is responsible for the drug’s psychoactive effects. Based on data from two different studies, potency increased from about 4 percent THC in 1995 to about 12 percent in 2014. By 2017, another study showed, the potency of illicit drug samples had gone up to 17.1 percent THC.
“That’s an increase of more than 300 percent from 1995 to about 2017,” says Staci Gruber, director of the Marijuana Investigations for Neuroscientific Discovery (MIND) program at the Harvard-affiliated McLean Hospital in Belmont, Mass. “I would say that’s a considerable increase.”
According to Gruber, the potency of concentrated forms of cannabis can be even higher in hash or hash oil, which can be 80 to 90 percent THC. “I think most people are aware of the phenomenon that ‘this is not your grand daddy’s weed,'” Gruber said. “I hear this all the time.”
In 2018, it was found that the average potency of legal marijuana products sold in the state of Washington, for example, is 20 percent THC, with some products being significantly higher.
The Washington Post points out that potency is rising in both the legal and illegal market for one reason: to convey an advantage to the seller. It’s all about developing a good customer base and making a profit. The more potent the drug, the better the chance that the user will become addicted and come back for more.
medicinale cannabis. dronabinol (THC) 19%;
cannabidiol (CDB)
There are some serious health effect related to high THC levels
A study published in 2016 in the U.S. found that there is a shift in the production of illicit cannabis plant material from regular marijuana to sinsemilla. This increase in potency poses a higher risk of cannabis use, particularly among adolescents.
Sinsemilla is a highly potent marijuana from female plants that are specially tended and kept seedless by preventing pollination in order to induce a high resin content. A sinsemilla plant contains a high percentage of THC’s, often around 10 percent or more. This figure increases to 20, 25 or even 30 percent if the plants are grown using hydroponic techniques.
In a study published in Psychological Medicine in 2018, researchers conducted a 16-year observational study and found a positive time-dependent association between changes in cannabis potency and first-time cannabis admissions to drug treatment.
“In general, people think, ‘Oh, I don’t have to worry about marijuana. It’s a safe drug,’ ” says Nora Volkow, director of the National Institute on Drug Abuse. “The notion that it is a completely safe drug is incorrect when you start to address the consequences of this very high content of 9THC.”
It might seem strange, but THC can have opposite effects on our bodies at high and low doses, says Volkow. She uses anxiety as an example: “When someone takes marijuana at a low [THC] content to relax and to stone out, actually, it decreases your anxiety,” she says. But high concentrations can cause panic attacks, and if someone consumes high-enough levels of THC, “you become full-blown psychotic and paranoid.”
The level of THC can also affect the vascular system. Volkow says: “If you take low-content THC it will increase your blood flow, but high content [THC] can produce massive vasoconstriction, it decreases the flow through the vessels.”
Many cancer patients use cannabis to ease the pain and nausea associated with chemotherapy, and cannabis does work. However, Volkow says, “patients that consume high content THC chronically came to the emergency department with a syndrome where they couldn’t stop vomiting and with intense abdominal pain.” The condition is called cannabinoid hyperemesis syndrome.
“The typical patient uses [inhales] about 10 times per day … and they come in with really difficult to treat nausea and vomiting,” says Andrew Monte, an associate professor of emergency medicine and medical toxicology at the University of Colorado’s school of medicine. “Some people have died from this … syndrome, so that is concerning.”
The best data on ER visits associated with marijuana use available in the U.S. comes from Colorado. In a study published in April 2019, Monte and his colleagues documented the rise in the number of cases at emergency rooms in Colorado since marijuana was legalized statewide five years ago.
Monte says it was found that cyclical vomiting cases made up about 18 percent of inhaled cannabis-related cases at his ER. He adds that his ER has “seen an approximately three-fold increase in emergency department visits just by frequency. It doesn’t mean we’re getting overwhelmed by these visits due to cannabis, it’s just that means that there are more patients overall.”
“We’re seeing an increase in psychosis and hallucinations, as well as anxiety and even depression and suicidality,” Monte says. And he believes the increased potency of marijuana plays a role in all these cases.
