Cannabis and schizophrenia: what is the connection?


Cannabis products are a booming business, but are you unknowingly increasing your chances of developing schizophrenia?

“Cannabis and schizophrenia” sounds like a slogan intended to instill fear in those who use different cannabis products, such as CBD and medical or recreational cannabis.

Although cannabis has been the subject of much political and scientific scrutiny over the years, it is not without drawbacks, like most natural and manufactured substances.

Not everyone who uses cannabis will develop schizophrenia, but for a small segment of the population this possibility can be very real.

Is CBD legal? The 2018 Farm Bill removed hemp from the legal definition of marijuana in the Controlled Substances Act. This made certain hemp-derived CBD products containing less than 0.3% THC federally legal. However, CBD products containing more than 0.3% THC still fall under the legal definition of marijuana, making them illegal federally but legal under some state laws. Be sure to check state laws, especially when travelling. Also keep in mind that the FDA has not approved non-prescription CBD products and some products may be inaccurately labeled.

Schizophrenia is a mental health disorder that involves gaps in your reality, known as psychotic symptoms or psychosis.

A systematic 2020 review reviewed 96 studies on cannabis and schizophrenia. After submitting the articles for quality assessment, only 12 were judged to be of high enough quality to be included in the review.

From these studies, the researchers found:

  • There may be a high frequency of psychotic disorders in people who use cannabis.
  • Cannabis use can alter the typical age and onset of symptoms of schizophrenia.
  • Cannabis-induced psychosis can eventually develop into clinical schizophrenia.
  • People living with psychotic disorders have a higher tendency to use cannabis.
  • Living with psychotic disorders can increase susceptibility to the psychoactive effects of THC.
  • Frequent cannabis use, especially at a young age, can double the risk of developing schizophrenia.
  • Daily use of high potency THC can lead to a 5 times higher risk of developing a psychotic illness.
  • Cannabis use may interact with pre-existing factors, such as genetics, to increase the risk of schizophrenia.

Cannabis does not cause schizophrenia.

But if you’re already predisposed to schizophrenia through genetic and environmental factors, cannabis use may increase your chances of developing schizophrenia.

This may be, in part, due to a natural sensitivity you may have towards the psychoactive effects of THC.

Symptoms of psychosis are related to a disconnection from reality.

For example, you can see, hear, smell, taste, or touch things that aren’t there. Your thoughts may not make sense, or you may have false beliefs known as delusions.

For cannabis users, these experiences may seem innocuous and familiar.

Higher doses of THC, a psychoactive compound in cannabis, are known to affect regions of the brain related to sensory and time perception.

It is not uncommon for people who use cannabis to experience symptoms of psychosis seen in schizophrenia, including:

  • Hallucination: characterized by false sensory experiences.
  • Delusions: thoughts and beliefs that are false or do not correspond to reality.
  • Disorganized thinking: nonsensical thought and speech patterns ranging from subtle to difficult to understand.
  • Negative symptoms: reduction in certain functional domains, such as cognitive decline.

Cannabis use can also cause feelings of dissociation or a loss of your sense of personal identity.

Yes, cannabis can trigger acute psychosis without it progressing to schizophrenia.

Psychosis describes episodes of disconnection from reality. The causes of these symptoms can be many and complex and may not have to do with schizophrenia.

Not all cannabis use leads to psychosis. These experiences are usually related to high dose exposure to THC.

In a study 2021 across more than 109,000 people in the UK, researchers found that there may be a strong association between cannabis dose and the chances of experiencing one of four types of psychotic symptoms, including:

  • auditory hallucinations
  • visual hallucinations
  • delusion of persecution
  • reference delusion

Not all cannabis products contain THC.

Cannabidiol (CBD) is another compound found in the cannabis plant that may have therapeutic effects for schizophrenia. Unlike THC, CBD generally does not have psychoactive properties.

CBD can neutralize the effects of THC, and some research 2018 suggests it can help relieve the psychotic symptoms of schizophrenia as effectively as some prescription drugs – and with fewer side effects.

Other research 2017however, notes that CBD may increase experiences of hallucinations and negative symptoms in some people, even though it may improve other features of psychosis.

While many ongoing studies are still investigating the uses of cannabis products, such as CBD in treatment approaches for schizophrenia, these products are not yet considered mainstream.

Can you use cannabis to relieve the symptoms of schizophrenia?

The data of a 2020 review indicates that people with psychotic disorders are more likely than others to turn to cannabis use.

Researchers speculate that living with a psychotic disorder could make the effects of more enjoyable cannabis.

So, although you may think you feel better when using a cannabis product, it does not necessarily mean that this substance treats your schizophrenia or any other psychotic disorder.

A systematic review 2021 the trials found no changes in schizophrenia symptoms and cognition in people using smoked or oral THC. The same review also found CBD results to be inconclusive.

The cannabis industry is growing, and with it may be the interest of people who have never tried cannabis products before.

Cannabis is not the same as marijuana, although marijuana is a cannabis product.

Although links between cannabis and schizophrenia have been identified, the use of cannabis products does not “cause” schizophrenia.

If you develop schizophrenia after using cannabis, it’s likely because you live with an underlying predisposition to the disorder.

Genetics, your environment, and other physiological elements can interact with cannabis use, leading to the development of a psychotic disorder.

The symptoms of psychosis can be alarming. You may have hallucinations or delusions that may compromise your safety.

If you or someone you know is suffering from psychosis, calling your local first responder teams can help ensure they recover in a safe and secure environment.

In the United States and Canada, you can reach immediate emergency services by dialing 911.


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