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Erik Messamore, M.D., Ph.D., a pharmacologist and associate professor of psychiatry

NEOMED Professor Prescribes Caution Around Cannabis

What do consumers know about THC, the ingredient in marijuana that gets you high?

Not enough, says Erik Messamore, M.D., Ph.D., a pharmacologist and associate professor of psychiatry at Northeast Ohio Medical University who specializes in the treatment of schizophrenia. Dr. Messamore has been quoted in national stories recently, making his point that, “You can’t trust the people who sell the drugs to be upfront with the risk,” as he told the Associated Press.

The AP story noted that in Colorado, there has been a threefold increase in emergency room visits since the state legalized recreational marijuana five years ago.

Dr. Messamore advocates for warning labels on cannabis products, similar to those used on tobacco products.

Gladwell and The New Yorker

Earlier this year, Dr. Messamore was cited in an article by Malcolm Gladwell, “Is Marijuana As Safe As We Think?” in The New Yorker magazine. The author noted, “The typical concentration of THC, the psychoactive ingredient in marijuana, has gone from the low single digits to more than twenty per cent — from a swig of near-beer to a tequila shot.”

In the New Yorker article, Gladwell quotes from Alex Berenson’s book called Tell Your Children: The Truth About Marijuana, Mental Illness, and Violence in which the author spoke with Dr. Messamore and came away with this observation: Since the increase in marijuana use, Dr. Messamore has been seeing growing numbers of “otherwise stable middle-class professionals” who have developed a disease that “looked like schizophrenia, but it had developed later — and their prognosis seemed to be worse. Their delusions and paranoia hardly responded to antipsychotics.”

More information needed

How is it that cannabis, which is known for reducing anxiety, can also provoke anxiety? In an infographic*, Dr. Messamore explains.

But to understand the broader effects of cannabis – including correlations with psychosis, such as schizophrenia – much more work needs to be done, he says.

And he wants patients to understand how much is uncertain when they consume an edible or take a puff of this increasingly available drug.