What to Consider as Marijuana Becomes More Acceptable, More Available

The growing body of research about the medical uses of marijuana can make it possible to overlook the real risks that can also be associated with the drug. How marijuana should be regulated and used has strong advocates on both sides; it can be hard to find unbiased information about the benefits and risks.

The Truth About Using Marijuana, CBD, and Your Health

It’s important to have balanced discussions about marijuana and not just hear the two extreme points of view, says J. Michael Bostwick, MD, a psychiatrist at Mayo Clinic in Rochester, Minnesota. “There can be one side saying, ‘It’s fabulous, it’s wonderful, and everyone should be using it,’ and the other saying, ‘It’s a drug of the devil and no one should ever be doing it,’” he says. Consider the source when you read or hear anything about the good or bad of marijuana, he suggests. While some short- and long-term health risks of pot have been established, there are many unanswered questions about the connection between marijuana and schizophrenia. Here we answer the top questions you may have about what the risks might be, as well as what experts still don’t know for certain.

Can Marijuana Cause Psychosis?

Yes, it’s been shown that marijuana can cause psychosis, says David Streem, MD, a psychiatrist at Cleveland Clinic in Ohio. “Regular cannabis users suffer double the risk of developing psychosis, from 0.07 to 0.14 percent. It’s one of the few consistent findings in recent cannabis research,” says Dr. Streem, referencing results from research published in the journal Archives of General Psychiatry.

The Definition and Meaning of Psychosis

Psychosis is a symptom of schizophrenia and can include delusions and hallucinations. A person in a psychotic episode may experience depression, anxiety, trouble sleeping, social withdrawal, and difficulty functioning, according to the National Institute of Mental Health. The risk for psychosis is likely to increase as the potency of THC in cannabis increases, says Streem.

Marijuana Is Much More Potent Compared With 20 Years Ago

THC, which stands for delta-9-tetrahydrocannabinol, is the major psychoactive component of the marijuana plant and causes the euphoria or “high” that many people feel after using the drug. According to research published in April 2016 in the journal Biological Psychiatry, the level of THC has tripled, rising from approximately 4 percent in 1995 to 12 percent in 2014, making the effects of pot much stronger.

Does a Heavy Marijuana User Have an Increased Chance of Developing Schizophrenia?

It’s hard say with certainty that marijuana use directly leads to schizophrenia because of the limitations of the research; it doesn’t look at causation, but rather association, says Dr. Bostwick.

The Difference Between Causation and Association in Scientific Research

Association is established when you take a large population of people with a condition and then look at various things that they might have done, he says. When you identify a certain behavior, then you can begin to figure out if that behavior is associated with a greater likelihood of that person developing the condition, having the condition, or having the condition more intensely, says Bostwick. Marijuana use is associated with schizophrenia, but researchers can’t prove direct causation.

Using Marijuana Has Been Linked to Psychiatric Disorders

There is evidence that links marijuana use with an increased risk of psychiatric disorders, including schizophrenia, says Streem. “A 2002 study found the more marijuana an adult consumed, the higher their risk of developing schizophrenia. The authors concluded that 13 percent of the schizophrenia cases in their cohort could be attributed to smoking cannabis,” he says, referencing research published in the journal BMJ. Another study, published in the journal Schizophrenia Bulletin, showed that patients who use cannabis regularly and experience a first episode of psychosis could improve their prognosis if they quit using cannabis, states Streem.

Research published in January 2014 in the journal Schizophrenia Research looked at marijuana users with and without a family history of schizophrenia and compared them with users and non-users of the drug without a family history.

Data Suggests Some People May Be Especially at Risk for Schizophrenia

They found an increased risk of developing schizophrenia for the people with a family history of the condition, regardless of whether they had used pot. Researchers concluded that marijuana doesn’t cause schizophrenia by itself, but it may initiate the onset of the disease in a genetically predisposed person. “If you have psychotic illness in your family then you might want to be especially careful,” says Bostwick. “If you have a tendency to the illness yourself, using marijuana could bring the illness out sooner and more intensely," he says.

Does Marijuana Impact the Same Part of the Brain That Relates to Schizophrenia?

Cannabis causes massive releases of many neurochemicals, which makes it very difficult to know what all the effects may be, says Streem. Bostwick agrees that there are too many unknowns, both in the disease as well as the drug effects, to be able to pinpoint the chemicals or part of the brain affected, or to make this assertion.

One way to think about the relationship between schizophrenia and marijuana use is to look at the symptoms or behaviors of each, he says. “If you already have a tendency toward psychosis or paranoia due to one illness and then you start using a substance that has a tendency toward psychosis or paranoia on top of that, then you have a double effect thing going on,” he says.

Are the Risks of Marijuana Use Significant Enough to Warrant a Government Warning?

Currently the states are not aligned with the federal government, and are setting up their own rules — and every state is different, notes Bostwick. “The federal government still contends that marijuana is a schedule 1 drug with no medical uses,” he points out. “It’s difficult when you’re talking about an illegal substance. How do you warn people that marijuana is dangerous? Because by definition, presumably it is dangerous; that’s why it was made illegal in the first place,” says Bostwick. Streem believes there is enough evidence to issue a health warning, though he concedes that because marijuana is still an illegal drug in the eyes of the federal government, it would make a federally mandated warning “difficult but not impossible.”

Are There Other Drugs That Increase the Risk of Schizophrenia or Other Mental Disorders?

“Synthetic cannabinoids, like K2, as well as the drugs involved in the ‘bath salts’ crisis a few years ago can both cause delusions and hallucinations that sometimes don’t resolve completely,” notes Streem. Research published in June 2018 in the journal Frontiers of Public Health reported that chronic use of synthetic cannabinoids has been associated with serious psychiatric and medical conditions and even death. “Bath salts” are synthetic cathinones, a human-made stimulant that’s chemically related to cathinone, which is found in the khat plant and native to East Africa and southern Arabia. The human-made version is much stronger and can be very dangerous, according to the National Institute on Drug Abuse. Side effects can include paranoia, hallucinations, excited delirium, extreme agitation, and violent behavior.