Schizophrenia and Weed: Is Cannabis Helpful or Hurtful?

There is a strong connection between schizophrenia and weed. Learn about the risks of smoking cannabis and developing schizophrenia on HealthyPlace.

Researchers have found, and are continuing to find, a strong link between schizophrenia and weed. It’s been known that using marijuana daily can cause paranoia and psychosis (in short, experiencing hallucinations and delusions and not being able to distinguish them from reality). It also can create symptoms very much like the negative symptoms of schizophrenia: decreased motivation, loss of a sense of pleasure, flat emotions, and other, similar, experiences.

These schizophrenia-like symptoms come from cannabis use. Does that mean that there is a connection between schizophrenia and cannabis use? And can you develop schizophrenia from weed? Perhaps shockingly, the answer to both questions is yes (Drug-Induced Schizophrenia? Is It Possible?). In certain situations, cannabis can cause schizophrenia or initiate the onset of schizophrenia in someone at risk for developing it.

Schizophrenia and Cannabis Use: Limited Benefits

Researchers worldwide and from many backgrounds have been conducting numerous studies to determine what causes schizophrenia and how it can best be treated. The link between schizophrenia and weed is a focus of many such studies.

Proponents of medical marijuana have discovered that using cannabis medically can ease some of the symptoms of schizophrenia—if you are an adult. Their research also shows that the helpful nature of weed for people with schizophrenia is limited because while some people do experience a lessening of symptoms, others find that their symptoms worsen, sometimes drastically.

Schizophrenia and Cannabis Use: Biologically Related Risks

Studies conducted around the globe consistently show that there is a strong link between schizophrenia and weed, especially when there’s a family history of mental illness (Marijuana/Cannabis and schizophrenia, n.d.).

When someone with family members who have schizophrenia or another mental disorder uses cannabis, his or her risk of developing schizophrenia skyrockets and is ten times higher than the average population. This means that the chance of developing schizophrenia from cannabis is 1000% more when there is mental illness in someone’s genetic makeup (Marijuana/Cannabis and schizophrenia, n.d.)

A combination of genetic factors and cannabis use adds up to a huge risk of developing schizophrenia. Marijuana can be a cause, and genetics can be a cause. Adding on one more crucial component produces the perfect storm for the onset of schizophrenia: age.

Schizophrenia and Smoking Weed: Huge Risk for Teens

In adolescence and early adulthood, there is a strong link between schizophrenia and weed. Smoking marijuana more than doubles a teen’s risk of developing schizophrenia (Silverstein, Spaulding, & Menditto, 2006). The National Institute on Drug Abuse cites studies that show that cannabis use increases the schizophrenia risk by four times. Other studies show a similar, striking relationship between schizophrenia and cannabis, especially in people under the age of 21.

The reason that schizophrenia and weed are so strongly correlated in the teen years is that the brain is very vulnerable in this stage of life. It’s still developing and is highly susceptible to outside influences such as cannabis. The younger the teen, the greater the risk that cannabis will cause schizophrenia, especially if the genetic component is present (What Are the Schizophrenia Symptoms in Children and Teens?).

Researchers are discovering that the chemicals in cannabis drastically alter the way the brain develops. In particular, using cannabis while the brain is still developing boosts dopamine to unnaturally high levels. The high dopamine levels are directly linked to schizophrenia.

Schizophrenia and weed are strongly connected, and smoking weed can lead to the development of schizophrenia, especially in a developing brain with a genetic predisposition to mental illness. Of course, not everyone who smokes weed will get schizophrenia. But there is enough evidence that cannabis use can and does cause schizophrenia to warrant being cautious—and to make teens aware of the risk.

This statistic about the link between schizophrenia and cannabis highlights the extent of the risk: “Experts estimate that between eight percent and 13 percent of all schizophrenia cases are linked to marijuana/cannabis use during teen years” (Marijuana/Cannabis and schizophrenia, n.d.).

If your brain is still developing, and/or if you have a family history of mental illness, push away the weed. It’s simply not worth the risk.

APA Reference
Peterson, T. (2021, December 28). Schizophrenia and Weed: Is Cannabis Helpful or Hurtful?, HealthyPlace. Retrieved on 2024, July 23 from

Last Updated: March 25, 2022

Medically reviewed by Harry Croft, MD

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