Harvard researchers published a study last week with the opposite findings of this study — that marijuana use doesn’t cause or lead to schizophrenia.
Researchers from Northwestern University reported Monday that chronic teenage use of marijuana contributes to changes in a person’s brain structure to resemble that of a person with schizophrenia, often resulting in memory issues.
Release of the research comes about a week after Uruguay became the first nation to legalize marijuana use for Uruguayans 18 and older, and after months of increased support from the general American public to end the prohibition of marijuana, prompting some to wonder if the release of this research is a last ploy to keep marijuana illegal?
Published in the journal Schizophrenia Bulletin, the study does not indicate whether marijuana use is the cause of the brain abnormalities, or if the consumption of the substance is merely correlated to the structural brain changes. But that hasn’t stopped the study’s authors from arguing that teenage use of marijuana not only affects a person’s memory, but also often leads to poor academic performance and a decline in an individual’s everyday functioning.
“We see that adolescents are at a very vulnerable stage neurodevelopmentally,” said Matthew Smith, who led the research team at Northwestern University’s Feinberg School of Medicine in Chicago. “And if you throw stuff into the brain that’s not supposed to be there, there are long-term implications for their development.”
Smith and his fellow researchers said that based on the study’s results, marijuana should not be decriminalized, let alone legalized in the U.S. — since marijuana is already the most commonly used illicit drug in the United States — reasoning that lax laws may only lead to greater use of the drug.
“The abuse of popular street drugs, such as marijuana, may have dangerous implications for young people who are developing or have developed mental disorders,” said co-senior study author John Csernansky, M.D., chair of psychiatry and behavioral sciences at Northwestern University’s Feinberg School of Medicine and Northwestern Memorial Hospital.
Though the mainstream media appears to have latched on to this particular study linking teenage marijuana use to a possible mental health illness and renewing the debate on the safety of pediatric medical marijuana, this is not the first study questioning youth usage — a fact even the researchers themselves acknowledged in their study.
The study isn’t even the only one to examine youth usage and schizophrenia in the last month.
Researchers at Harvard University published a study last week that had the opposite findings of this study — that marijuana use doesn’t cause or lead to schizophrenia. But as Paul Armentano, deputy director of the legalization advocacy group the National Organization for the Reform of Marijuana Laws, told MintPress, the media failed to largely report on that study or link the two together.
Armentano called coverage of the Northwestern study ironic given that the Harvard study received little media attention, and said it’s arrogant for the mainstream media to report on a single report as if no other research on the subject exists, and said in 2013 alone there has been more than 1,500 scientific papers on cannabis.
He added that studies regarding the safety and health effects of marijuana have been around for decades and pointed to the findings of a similar ‘marijuana leads to schizophrenia’ study, which found that although marijuana use increased in the U.K. from 1996 to 2005, the “incidence and prevalence of schizophrenia and psychoses were either stable or declining.”
If there was a direct link between marijuana use triggering schizophrenia, Armentano says we would know by now. “Marijuana and people using it is not a new phenomenon,” he said, adding that if the drug significantly impaired a person’s long-term brain function, scientists wouldn’t need brain imaging devices to see the effects of the drug.
In a post on the Toke Signals website earlier this year, Steve Elliott, editor and host of Toke Signals.com, a Seattle Weekly columnist and author of “The Little Black Book of Marijuana,” said that every few months another “scientific” study attempts to make “Reefer Madness” connections between a person’s sanity and marijuana use.
“Considering modern rates of usage, if cannabis really produced psychosis, the streets would be choked with a gibbering throng of burned-out potheads. It doesn’t. They aren’t,” Elliott said.
Armentano added that although there are also studies saying that smoking marijuana can “double” the risk of psychosis or schizophrenia “there exists no empirical evidence anywhere on Earth indicating that populations which have experienced rising rates of cannabis use have also experienced a parallel increase in rates of mental illness.”
Still, he says “we don’t want young people using intoxicants during formative years when their brain is developing.” He compared teenage use of marijuana to substances like alcohol and tobacco, and said that instead of enacting blanket prohibition on substances not suitable for children, the U.S. should enact public education campaigns and increase regulations on the product.
Marijuana and mental health
Dr. Mitch Earleywine is a professor of psychology at State University of New York at Albany, and a NORML board member. In an email to MintPress, Earleywine said that while a teenager should not use marijuana every day for three years, “a close look at these data and recent meta-analyses of cognitive effects of cannabis reveals that the problems with working memory are actually very small.”
He continued to say that in his own research, he has found that “cannabis users can perform poorly on memory tests simply because they’ve been told that they will fare poorly.
“Coming into a lab where you know that the investigators expect you to flub a test can, in fact, make you flub a test. So cannabis likely does not create any of the deficits that have become the stereotype in cannabis-related comedies or alarmist, misinformed prevention efforts.
“In addition, working memory deficits appear in a host of disorders, not just schizophrenia. These deficits often accompany depression and anxiety– the very disorders that might lead teens to turn to cannabis in the first place. As the authors of the Schizophrenia Bulletin study emphasize, these new data are correlation. It is distinctly possible that the memory deficits existed prior to any exposure to cannabis.”
He concluded by saying that while “teen cannabis use has been associated with changes in brain structure before, but the effects seem hard to replicate … The findings in the Schizophrenia Bulletin study make for a nice story, but until the results replicate, we should interpret them with extreme caution.”
Although marijuana hasn’t been found to have a causal relationship with mental illnesses such as schizophrenia, Armentano says that use of the substance can correlate with mental illness for several different reasons.
“People often turn to cannabis to alleviate the symptoms of distress,” he said. “One study performed in Germany showed that cannabis offsets certain cognitive declines in schizophrenic patients. Another study demonstrated that psychotic symptoms predict later use of cannabis, suggesting that people might turn to the plant for help rather than become ill after use.”
Armentano also said a non-causal association could exist between marijuana use and psychosis because the symptoms of mental illness often occur during one’s teenage years, which is when young people are likely experiment with marijuana.
Regulation is key
But just because there may be a link between marijuana use and mental health issues, Armentano says the government should not keep marijuana as an illegal substance. Instead, he says health risks connected with pot use — when scientifically documented — should not be seen as legitimate reasons for criminal prohibition, but instead as reasons for the plant’s legal regulation.
“We don’t outlaw peanuts because a small percentage of people have allergic reactions,” Armentano said. “We educate the community; we regulate where and when peanuts can be exchanged. That seems like it ought to apply to marijuana, too.
Another example Armentano gave was regarding the safety of ibuprofen. Though the over-the-counter medication may be used by the masses, ibuprofen can be quite damaging to those Americans with liver and kidney problems. Still, Armentano says the product is widely available and not criminalized by the federal government, which is what he argues should happen with cannabis.
Armentano also pointed out that the teenagers in the study had unusually high usage patterns for their demographic, in that they consumed cannabis every day for three years, which is considered heavy use for recreational users of that age group. And reiterated his point that if anything, the study illustrates a need for increased regulations and legalization of a substance that is currently unregulated and uncontrolled.
Steph Sherer is the executive director of the medical marijuana advocacy group Americans for Safe Access, which launched a program this week that will certify the quality and reliability of medical marijuana products sold at licensed businesses. She agrees with Armentano that more regulation is needed in the industry, since patients want to know that their medicine is as safe as possible, which includes testing for contaminants such as mold, mildew and pesticides.
Sherer told MintPress that many companies do a really great job of checking for contaminants along with potency of a specific strain of marijuana, but there are some dispensaries that could improve — especially because as the industry and demand for marijuana grows, the plant is being produced in larger quantities and stored for longer periods of time.
Although there is some research on what happens to the human body when mold and mildew is ingested, “we know very little about how pesticides react to the body,” Sherer said. But as the industry starts to flourish, Sherer says researchers are looking more into contaminants’ effect on the body. She pointed to the findings of a study released last month in the journal Toxicology, which showed that when a person uses marijuana that has pesticides on it, the pesticides go into the user’s lungs.
“Every industry in this country that has a commercial sale component has regulation,” Sherer said, explaining that this is why ASA believes it’s important that the marijuana industry follow in the footsteps of other botanical and herbal medicine regulations.