As more states legalize marijuana, more people in the U.S. are buying and using weed – and the kind of weed they can buy has become much stronger.
That concerns scientists who study marijuana and its effects on the body, as well as emergency room doctors who say they’re starting to see more patients who come into the ER with weed-associated issues.
Some 26 million Americans ages 12 and older reported being current marijuana users in 2017, according to the National Survey on Drug Use and Health. It’s not clear how many users have had serious health issues from strong weed, and there’s a lot that’s still unknown about the potential risks. But scientists are starting to learn more about some of them.
The potency of weed depends on the amount of delta-9-tetrahydrocannabinol, or THC, the main compound responsible for the drug’s psychoactive effects. One study of pot products seized by the U.S. Drug Enforcement Administration found the potency increased from about 4% THC in 1995 to about 12% in 2014. By 2017, another study showed, the potency of illicit drug samples had gone up to 17.1% THC.
“That’s an increase of more than 300% 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.”
And some products with concentrated forms of cannabis, like hash and hash oil, can have as much as 80% to 90% THC, she adds.
“I think most people are aware of the phenomenon that ‘this is not your grand daddy’s weed,’ Gruber says. “I hear this all the time.”
But people might not be aware of the potential health risks of highly potent weed. “The negative effects of cannabis have primarily been isolated and localized to THC,” says Gruber. “So it stands to reason that higher levels of THC may in fact confer a greater risk for negative outcome.”
“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 completely safe drug is incorrect when you start to address the consequences of this very high content of 9THC.”
Pot’s paradoxical effects
THC can have opposite effects on our bodies at high and low doses, Volkow says. Take anxiety levels, for 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.”
Weed can have a similar paradoxical effect on 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.”
And at low concentrations, THC can be used to treat nausea in cancer patients undergoing chemotherapy. But Volkow says that “patients …read more
Source:: Daily times