The relationship between weed, or cannabis, and schizophrenia is complex. Cannabidiol (CBD), a chemical substance in cannabis, could help manage schizophrenia. However, tetrahydrocannabinol (THC), another compound in the plant, may induce or exacerbate the condition. Doctors do not currently recommend cannabis to treat people with schizophrenia.

Cannabis is a natural plant with recreational and medicinal properties. Researchers continue to investigate the potential health benefits of the plant and how it may affect physical and mental health. Cannabis contains many cannabinoids, with two notable compounds being CBD and THC.

This article will explore the connection between cannabis and schizophrenia and whether people living with schizophrenia can use cannabis.

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Schizophrenia is a mental health condition affecting speech, thinking, and emotions. A person may receive a diagnosis of schizophrenia if they display at least two of the following symptoms over a significant amount of time:

  • delusions
  • hallucinations
  • disorganized speech
  • very disorganized or catatonic behavior
  • symptoms people may describe as negative, including reduced emotional expression

The condition may develop due to a combination of specific genetic and environmental factors. As such, some people and their lifestyle choices may make them more likely to develop schizophrenia.

A 2017 study suggests that some substances in cannabis could trigger the condition in susceptible individuals who were likely to develop schizophrenia. However, it can be difficult to distinguish symptoms between schizophrenia and drug-induced psychosis.

A 2020 review highlights that THC may have a causative effect on schizophrenia. Some evidence suggests that the substance could also worsen schizophrenia symptoms, such as psychosis, and result in more relapses and hospitalizations. However, many of the studies in the review did not have a consistent evaluation of the condition. Additionally, the review also notes the therapeutic potential of CBD.

Another 2017 study suggests that CBD may have beneficial effects and could help lower levels of schizophrenia symptoms. Similarly, a 2019 review adds that CBD may offer a promising option for people with schizophrenia and could represent a new class of treatment for the condition.

A 2021 systematic review notes there is currently insufficient evidence for the effect of THC or CBD on schizophrenia. As such, it does not recommend using recreational or medical cannabis to treat the condition, indicating the need for further research.

According to the 2020 review, cannabis use may result in several risks for people with schizophrenia. For instance, those who use cannabis after their first acute psychotic episode often respond less well to medication. Similarly, after a schizophrenia diagnosis, people who use cannabis chronically or heavily are more likely to:

  • experience a relapse in symptoms
  • experience worsening symptoms
  • have longer hospitalization periods

These negative effects may occur even if the individual is taking their schizophrenia medication.

There is also evidence that cannabis use may cause schizophrenia in people with a predisposition to the condition. Some research notes that cannabis use may increase the risk of schizophrenia by 40%. However, scientists remain uncertain about the exact link.

A 2020 study notes that cannabis use can cause drug-induced psychosis, which may transition into schizophrenia in up to 25% of cases. Cannabis-induced psychosis is the drug-induced psychosis most likely to transition into schizophrenia.

Cannabis has several active ingredients, including THC and CBD. While there is some evidence to suggest that THC worsens the symptoms of schizophrenia, other research suggests that CBD might have the opposite effect, particularly for improving symptoms of psychosis.

As a 2020 review explains, some research suggests that in some cases, both psychotic and cognitive symptoms of schizophrenia improve in those taking CBD for an extended time. A 2021 study also adds that CBD could offer a suitable alternative to antipsychotic medications.

However, it is worth noting that if a person uses cannabis instead of CBD isolate, which does not contain any THC, they will likely expose themselves to THC. This may counteract the possible therapeutic benefits of CBD.

CBD is yet to receive approval for treating schizophrenia, and a 2022 narrative review concludes that more research is necessary. However, the authors add that there is sufficient evidence to suggest the promising beneficial effects of CBD in treating those with schizophrenia.

When treating schizophrenia, several different therapeutic options are available. As each person’s experience of schizophrenia will be different, a doctor or psychiatrist will tailor the treatment to suit the individual. Typically, initial treatments will involve the use of antipsychotic drugs. Examples of these may include:

People with schizophrenia can also benefit from nondrug interventions. These might include:

  • cognitive behavioral therapy
  • art therapy
  • drama therapy
  • counseling
  • coordinated special care

Anyone who suspects they may be presenting signs of schizophrenia should consult a doctor. The severity, duration, and frequency of symptoms can vary, and the use of illegal drugs can increase symptoms. Possible symptoms of schizophrenia may include:

  • hallucinations
  • delusions
  • disorganized, unfocused, or incoherent speech
  • highly disorganized behavior
  • catatonic behavior
  • diminished emotional expression
  • lack of motivation

If a person notices certain negative behaviors or symptoms that frequently occur following cannabis use, it may be advisable for them to stop using it and contact their doctor.

Schizophrenia is a mental health condition that affects a person’s thoughts, emotions, and behavior. Various factors can contribute to developing this condition, and they may include the use of certain drugs, such as cannabis, in susceptible individuals.

As such, doctors do not currently recommend cannabis use for people with schizophrenia. This is because THC present in the plant may exacerbate symptoms. However, research suggests that CBD, another chemical present in cannabis, may be a useful treatment option. However, further research is necessary to explore CBD’s therapeutic benefits.