Heavy cannabis use linked to schizophrenia in young men: study

Young men who are heavy weed smokers could have a higher risk for developing schizophrenia, according to a new study.

The research, which was published on May 4 in the journal Psychological Medicine, found that a shocking 30% of schizophrenia cases among men aged 21 to 30 could have been thwarted if they had averted cannabis use disorder.

Scientists examined recent cases of schizophrenia, an abnormal interpretation of reality resulting in hallucinations, delusions or disordered thinking. The study’s authors stated that in 2021, CUD played an integral role in 15% of cases occurring in men aged 16 to 49, and in 4% of cases affecting women in the same age range.

CUD is defined by the Centers for Disease Control and Prevention as the inability to stop using marijuana despite negative impacts on one’s health and social life.

According to the Centers for Disease Control, it affects 3 in 10 marijuana smokers.

The new study examined data concerning 6.9 million people ages 16 to 49 collected in Denmark from 1972 to 2021.

Young men may be more at risk because historically men are more likely than women to develop schizophrenia, and also because a greater number of men smoke marijuana.

“When you’re looking at cannabis use, or substance use in general, men tend to be on the higher end of the [consumption] spectrum than women,” Dr. Scott Krakower, a psychiatrist at Northwell Health’s Zucker Hillside Hospital, told The Post. “They may also be more prone to sensation-seeking behavior.”

Krakower said he could see how heavy marijuana consumption in young men could be linked to a schizophrenia diagnosis, but quantifying how much marijuana consumption would make a difference is unclear.

But, legalized weed and limited regulation certainly isn’t helping, the doctor noted.

“A kid could smoke a lot and nothing is going to happen to them [but] god forbid your kid is predisposed and they get a psychotic disorder,” he said.

He added that excessive marijuana use in one’s teens is especially dangerous, as it can impact overall brain development and even cause some changes to its anatomy.

“The brain is at its peak developmental years from 12 to 20,” Krakower said. “When marijuana comes into the picture, the normal brain development is impaired.”

“There could be changes to the overall neuroplasticity and neurocircuitry … changes to serotonin, changes to dopamine, histamine, all these things are responsible for executive functioning and for how we perceive the world,” he continued. “When cannabis oversaturates the system it can trigger higher levels of anxiety, cognitive delays, memory loss.”

Teen are also more likely to develop a problem with the drug.

According to a report by the National Institute on Drug Abuse published in March 2021, those aged 12 to 17 are more apt than those aged 18 to 25 to become addicted to marijuana within a year after using it for the first time.

The Danish study determined that while cannabis use disorder is not responsible for most schizophrenia cases in Denmark specifically, marijuana consumption has contributed to a rise in schizophrenia in the last 50 years.

Researchers say one possible reason is that cannabis is both more accessible and more powerful than ever.

They found that the amount of THC — the major psychoactive component in marijuana — in weed in the US rose from 10% in 2009 to 14% in 2019.

In Denmark, it was 13% in 2006 and 30% in 2016.

THC in weed was typically less than 1.5% in 1980, according to previous research published in the Journal of Forensic Sciences.

Today, some cannabis products even contain upward of 30%.

Some concentrated products such as oils and edibles can have above 95%. 

“A lot of these products are mislabeled. When you’re looking at the weed market, nothing is regulated — you always have to know in the back of your head if you’re having 5 mg you might be having 10 or 15, there’s no way of knowing,” Krakower said.

“The problem is, people forget that marijuana is still a substance no matter how we look at it. Parents need to understand that it’s not healthy.”