Does Cannabis Help Improve Schizophrenia Symptoms?

Schizophrenia is a complex mental health condition that can cause serious disruptions in all areas of life. It manifests in multiple layers of symptoms that affect:

  • Thinking
  • Behavior
  • Movement

Although cannabis can provide relief from the symptoms of several mental illnesses, the relationship between cannabis and schizophrenia is more complicated.

A growing body of research reveals that tetrahydrocannabinol (THC), the psychoactive compound responsible for marijuana’s famous high, can worsen symptoms of schizophrenia.

Interestingly, cannabidiol (CBD), the cannabis compound that doesn’t cause consumers to feel psychoactive effects, appears able to relieve schizophrenia symptoms.


What Is Schizophrenia?

More than 50 million people worldwide have schizophrenia. This serious disorder can affect just about every demographic group, even children, although it most commonly develops between the ages of 16 and 30.

There’s no laboratory test to diagnose schizophrenia, but a diagnosis is usually made by observing the presence of three different types of symptoms:

  • Positive symptoms are those of psychosis, or a “break from reality.” These symptoms include:
  • Hallucinations
  • Delusions
  • Paranoia
  • Disorganized thinking
  • Unusual patterns of movement
  • Negative symptoms involve emotional responses. These can include:
  • A flat affect, or minimal emotional responses under any circumstances
  • Lack of feelings of pleasure in life
  • Reduced speaking
  • Inability to start and finish activities
  • Cognitive symptoms involve thinking, decision making and memory. These symptoms can affect the schizophrenia sufferer in large or small ways and include executive functions like:
  • Using information to make choices
  • Controlling impulses
  • Remembering information

Why Do Some People Develop Schizophrenia?

Genetic factors play a major role in determining who develops schizophrenia, but they aren’t the only ones. Dysfunctions in several areas of the brain, where neural processing involving emotion, motivation and thinking take place, also play a part.

People with schizophrenia have abnormal functioning in the hippocampus, which is strongly associated with emotions. They also seem to display abnormalities in the neural pathways related to the processing of glutamate and dopamine, two brain chemicals that help to regulate mood and cognition.

Schizophrenia sufferers may also have dysfunction in the production of a protein called brain-derived neurotropic factor (BDNF), which plays a key role in keeping neurons healthy. In some animal studies, introducing BDNF has been shown to prevent the development of schizophrenia.

Research reveals that environmental factors can also play a role. Researchers have studied various factors that predispose someone to schizophrenia such as:

  • Exposure to certain viruses
  • Malnutrition before birth
  • Trauma during birth
  • Childhood abuse

Cannabis has also been linked to the development of schizophrenia, especially when smoked by susceptible teens and adolescents.

Whatever the causes, doctors usually treat schizophrenia with one or a combination of powerful antipsychotic drugs designed mainly to control the positive symptoms that can cause severe psychotic episodes. These drugs range from the older Thorazine and Haldol to newer medications like Risperdal, Abilify and Seroquel.

But all of them have a number of side effects, such as:

  • Weight gain
  • Tardive dyskinesia, a tremor that may become permanent.

Because most people must take these medications for life, the search continues for safer alternatives—and this could include cannabis.

How Cannabis Affects Schizophrenia

The two most abundant compounds in cannabis are CBD and THC, the ingredient that can cause either a relaxing high, or in some people, produce extreme anxiety, paranoia and even psychosis.

Some studies have suggested a link between cannabis consumption and the risk of developing schizophrenia, especially among young consumers. According to these studies, teen brains are still forming, so that ingesting a lot of cannabis, typically by smoking, at this age can disrupt the developing neural pathways in the brain. And this can make these consumers more susceptible to developing schizophrenia, especially if they already have a genetic predisposition.

In addition, consuming cannabis that contains THC has been shown to worsen not just the positive symptoms of psychosis, but also all kinds of schizophrenia symptoms in people who already have the disorder.

According to HelloMD’s Dr. Richard Kim, “Recent research strongly indicates that THC use is directly implicated in the development of a first psychotic episode. It’s also linked to an increase in frequency and intensity of psychotic episodes in those who are genetically predisposed to develop schizophrenia.

“Also, THC has been shown to significantly worsen the progression of the disease; positive, negative and cognitive symptoms are all negatively affected when schizophrenia patients use THC.”

CBD May Relieve Schizophrenia Symptoms

CBD doesn’t cause any mood-altering effects. It has also been shown to moderate the effects of THC, so that they don’t get out of control.

CBD also has considerable anti-inflammatory and neuroprotective powers, and it acts on multiple pathways in the brain to regulate the functions of neurotransmitters related to mood and thinking, like dopamine, serotonin and glutamate.


This explains why CBD can be effective in treating conditions like anxiety and depression, as well as memory disorders caused by Alzheimer’s disease, traumatic brain injury and other kinds of dementia.

Standard antipsychotic medications typically target the positive symptoms of schizophrenia such as delusions and hallucinations. But research now suggests that CBD may also improve both positive and negative symptoms of schizophrenia as well as cognitive functioning.

Dr. Kim points out that a 2012 clinical trial demonstrated how CBD helped schizophrenia sufferers: “A very recent clinical study suggests that CBD may also improve positive and negative symptoms, as well as cognitive functioning in people with schizophrenia already prescribed with an antipsychotic medication.”

And, since CBD doesn’t affect the secretion of a hormone called prolactin, it doesn’t cause the side effects such as weight gain, hormone imbalances and sexual dysfunctions that are common with antipsychotic drugs.

Schizophrenia is a complicated disorder, and it has a complicated relationship with cannabis, too. For people who are susceptible to schizophrenia or who already have it, THC can trigger or worsen symptoms.

But the mood-boosting properties of CBD have the potential to relieve schizophrenia symptoms of all kinds—without the risks and side effects of standard antipsychotic medications.

Photo credit: Callie Gibson

If you’re new to cannabis and want to learn more, take a look at our Cannabis 101 index of articles. And if you have questions about cannabis, ask them and our community will answer.


Related Articles

The perfect dose of cannabis content

Delivered right to your inbox.

Scroll to Top