Fact Check: Can Marijuana Use Induce Schizophrenia?

Numerous studies have correlated marijuana use to an increased risk of psychiatric disorders, including schizophrenia. Schizophrenia is a chronic brain condition that affects nearly 20 million people worldwide, causing substantial disability and a high burden of care. To what extent marijuana use may cause psychiatric disorders is uncertain.

Youths who already have a mother, father, or sibling with schizophrenia are the most at risk. Young people with a parent or family member affected by psychosis have around a one in 10 chance of developing schizophrenia themselves, even if they never use marijuana. However, regular marijuana use may double that risk.

“Recent research suggests that smoking high-potency marijuana every day could increase the chances of developing psychosis by nearly five times compared to people who have never used marijuana.”

It appears that the frequency of marijuana usage, at what age usage began, and genetic variations all influence this relationship.

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Can marijuana cause schizophrenia?

The most substantial evidence linking marijuana use to psychiatric disorders occurs in users with pre-existing genetic vulnerabilities or other disabilities.

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Researchers for the National Epidemiological Survey on Alcohol and Related Conditions examined the association between marijuana use and mood, anxiety, and substance abuse disorders.

Their research found no association between marijuana use and mood/anxiety disorders, but marijuana use increased the risk of alcoholism, nicotine dependence, and other drug dependencies.

Other research has found that people who use marijuana daily AND carry a specific genetic variant in their striatum are seven times more 

likely to develop psychosis than those who use marijuana infrequently or never at all.

The striatum is an area of the brain that becomes activated and flooded with dopamine in response to stimuli.

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Marijuana use may worsen the illness in patients who already have schizophrenia.

Marijuana can produce a small psychotic reaction in non-schizophrenics who use marijuana, especially at high doses, although it fades as the drug’s effect wears off.

READ: Is Marijuana Medicine? The Good & Bad

Effects of marijuana use

Adverse consequences of marijuana use may include:

• Impaired short-term memory
• Impaired judgment, attention, and other cognitive functions
• Impaired physical reactions
• Increased heart rate
• Anxiety or paranoia

For these reasons, doctors recommend avoiding marijuana use:

• If you are a teen;
• If you have schizophrenia; or
• If someone in your family has a history of schizophrenia or other mental illnesses.