Marijuana and Schizophrenia

Frequent cannabis use is associated with schizophrenia and other psychotic disorders, according to multiple reports. Marijuana users with a history of psychiatric disorders or with certain genes have an increased risk for developing schizophrenia.
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Marijuana is classified as a Schedule I drug because it has a high potential for abuse and no accepted medical use in the United States. However, some people use the drug to treat the symptoms of schizophrenia, a serious mental disorder associated with mental impairment and psychotic episodes.

Research shows that marijuana can cause mental health problems such as anxiety and depression, and it increases the risk of schizophrenia in people who are genetically vulnerable to the disease. The substance also worsens psychotic symptoms and outcomes in people with schizophrenia,

What Is Schizophrenia?

Schizophrenia is a severe mental health condition that affects a person’s ability to think, feel and behave clearly. It is characterized by hallucinations, delusions and dysfunctional thinking. The disorder can also cause psychotic episodes.

Additional symptoms of schizophrenia include:

  • Reduced feelings of pleasure in life
  • Difficulty starting and continuing activities
  • Reduced speaking
  • Trouble focusing

Symptoms of schizophrenia generally begin between ages 16 and 30, but children can develop the disorder. Although schizophrenia is not as common as other mental health conditions, the symptoms can be severely debilitating.

Link Between Marijuana Use and Schizophrenia Risk

One of the most comprehensive evaluations on the health effects of marijuana was documented in a 2017 report by a committee appointed by the National Academies of Sciences, Engineering, and Medicine. The committee stated that substantial evidence shows cannabis use is associated with the development of schizophrenia and other psychoses.

In addition, people with schizophrenia have an increased risk for trying cannabis. The prevalence of marijuana use is generally higher among those with schizophrenia than it is among the general population, according to the committee’s report.

A number of factors influence the relationship between marijuana and schizophrenia, including:

  • Age at first use
  • How much of the drug is used
  • Frequency of use
  • A history of psychiatric disorders
  • Genetics

A 2017 study published in the journal Psychological Medicine examined the relationship between marijuana use and the risk for schizophrenia. Researchers found some evidence linking cannabis use with an increased risk for schizophrenia. This study also concluded that people at risk for schizophrenia are more likely to try cannabis.

Genetics strongly influence the development of schizophrenia in marijuana users. A 2012 study published in the journal Biological Psychiatry indicated that teen cannabis users with a gene called AKT1 can develop psychosis later in life.

The AKT1 gene tells the body how to make a protein that affects levels of the brain chemical dopamine. The Biological Psychology study found that daily marijuana users with a specific variant of AKT1 have a seven times higher risk of developing psychosis than those who use the drug infrequently or not at all.

Teens are particularly vulnerable to the effects of substance abuse because the brain doesn’t fully develop until age 25. A Harvard Medical School report cited a study of more than 50,000 young Swedish soldiers that found those who smoked cannabis were more than twice as likely to develop schizophrenia than those who had not smoked the drug.

Can Marijuana Treat Schizophrenia?

Some studies have suggested that marijuana could treat symptoms of schizophrenia. A 2017 study published in the journal Neuroscience & Biobehavioral Reviews suggested that the chemical cannabidiol, or CBD, found in the cannabis plant might improve brain function in people with schizophrenia.

The study’s authors, however, suggested that the effectiveness of CBD in improving cognition among this population cannot be fully explained because there is a lack of scientific evidence. They suggested that additional research be conducted to confirm this theory.

The 2017 National Academies of Sciences, Engineering, and Medicine report found little or no evidence that CBD effectively improves mental health outcomes in people with schizophrenia or schizophreniform psychosis.

However, the report also found moderate evidence that cannabis can lead to better cognitive performance among people with psychotic disorders, such as schizophrenia, and a history of cannabis use.

Treating a Marijuana Use Disorder and Schizophrenia

According to the Office of National Drug Control Policy, research shows that about 9 percent of marijuana users become dependent on the drug. Those who are dependent on marijuana need it to function normally. They experience withdrawal symptoms when the drug isn’t present.

Dependence can progress to addiction when people can’t quit marijuana even though it’s causing problems is their life. A number of individuals with marijuana addiction also experience mental health problems.

The most effective approach way for people with schizophrenia quit marijuana is to receive treatment for marijuana abuse and schizophrenia at the same time.

Schizophrenia requires lifelong treatment. Treatments for the disorder include antipsychotic medications, psychotherapy and social skills training. Hospitalization may be needed to ensure safety, adequate sleep and proper hygiene and nutrition.

A therapy technique called behavioral treatment for substance abuse in serious and persistent mental illness has shown to reduce drug abuse in people with schizophrenia, according to a 2009 study published in the Journal of Clinical Psychology.

The technique rewards people for positive drug tests and helps them set short-term goals. Patients also learn how to refuse drugs and avoid relapse. In addition to schizophrenia, other mental illnesses can be managed using this approach.

People who receive treatment for marijuana addiction can overcome cannabis dependence and symptoms of schizophrenia. The best rehab facilities treat both conditions simultaneously, providing evidence-based treatment catered to the patient’s specific needs.

Medical Disclaimer: aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.

Matt Gonzales
Content Writer,
Matt Gonzales is a writer and researcher for He graduated with a degree in journalism from East Carolina University and began his professional writing career in 2011. Matt covers the latest drug trends and shares inspirational stories of people who have overcome addiction. Certified by the Centers for Disease Control and Prevention in health literacy, Matt leverages his experience in addiction research to provide hope to those struggling with substance use disorders.

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