Cannabis may increase the risk of schizophrenia, particularly in people with a genetic predisposition to the condition.
Schizophrenia is a mental health condition that alters how people think, feel, and behave. It can cause psychosis, in which a person loses some contact with reality and may experience symptoms such as hallucinations and delusions.
Weed, which people may also refer to as cannabis, may be a risk factor for developing psychosis.
This article looks at the link between cannabis use and schizophrenia symptoms. It also outlines the treatment options and explains when to contact a doctor.
According to a 2021 article, cannabis use is a risk factor for developing or worsening an existing mental health condition.
Adolescents or young adults who consistently use cannabis may be at risk of developing a psychotic disorder, such as schizophrenia. Additionally, those with a
According to older 2015 research, up to 25% to 30% of people who visit the emergency department due to cannabis use will have symptoms such as:
- anxiety
- suicidal thoughts
- symptoms of psychosis, to varying degrees
The mind-altering component of cannabis is tetrahydrocannabinol (THC). Cannabis also contains other compounds that are chemically related to THC and are known as cannabinoids.
In people with schizophrenia, cannabis use may worsen the course of the condition.
Learn about CBD and THC.
According to a
Symptoms such as paranoia, anxiety, or psychosis may be present during the initial stage of intoxication. Impaired coordination and learning and sleep problems are among the effects that can last longer but may not be permanent.
Repeated use of cannabis can have cumulative effects that can cause long-term symptoms.
Doctors may diagnose cannabis intoxication when recent cannabis use has led to
The duration of symptoms can depend on a person’s tolerance and the dose they take.
Many people who present to the emergency department with psychotic symptoms relating to cannabis use will need hospitalization. Up to 50% of these individuals will develop schizophrenia.
Psychosis usually develops over time, with a person experiencing gradual changes in their thoughts and perceptions. They may be unaware of these changes.
Pre-psychosis symptoms are early warning signs of psychosis, according to the National Alliance on Mental Illness (NAMI). They include:
- a concerning decline in school grades or work performance
- difficulty concentrating or thinking clearly
- feeling suspicious or uneasy around others
- a decline in personal hygiene or self-care
- spending much more time alone than usual
- a lack of feelings or very strong, inappropriate emotions
The symptoms of psychosis
Delusions
Delusions are irrational, false beliefs or strong beliefs that are unusual for the person.
People experiencing them may think external forces are taking control of their thoughts and behaviors. They may believe that trivial objects have great significance, that they have superpowers, or that they are on a special mission.
Hallucinations
Hallucinations occur when people see, hear, or feel things or sensations that are not real.
Individuals may hear voices, experience strange sensations that they cannot explain, see things distortedly, or see objects or people that are not there.
Disorganized thoughts
People may have disorganized thoughts and speech patterns that seem jumbled and do not make much sense to others.
For instance, they may switch randomly from one topic to another or reply with an unrelated remark. Disorganized thought and speech can severely affect how individuals communicate.
Dissociation
Some people with schizophrenia may experience dissociation symptoms, such as a detached feeling or a disconnection from their body and the world around them.
A person may feel as though objects or people around them are not real. They may also be unable to remember information about themselves.
Emotion, mood, and behavioral changes
A person’s behavior and speech may change — they might speak in a monotone voice or lack facial expressions.
Their movements might suddenly become agitated or childlike. Alternatively, a person may become catatonic and have a very limited response to their surroundings.
Other common changes include social withdrawal and difficulty making decisions or carrying out everyday tasks.
Learn about the symptoms of schizophrenia.
For people in the early stages of psychosis, coordinated specialty care (CSC) may be an effective treatment. CSC involves a team of healthcare professionals working with the person and their family to provide:
- family support and education
- psychotherapy
- peer support
- support with education and employment
The treatment for psychosis or schizophrenia will include medications, such as antipsychotic drugs, and psychotherapy.
People may also require therapies that help reduce cannabis use. According to an older 2017 review, these may include:
- Cognitive behavioral therapy (CBT): CBT is a type of psychotherapy that gives people strategies to identify and change negative patterns of thought and behavior.
- Contingency management: This approach involves frequent monitoring of the behavior that a person is working to change and provides incentives or rewards for positive changes.
- Motivational enhancement therapy: This therapy aims to motivate someone to use their internal resources to engage in treatment and create positive changes.
Read about CBT for schizophrenia.
Anyone who experiences psychosis or pre-psychosis symptoms or notices them in someone else needs to contact a doctor. According to NAMI, early treatment can slow or stop psychosis and improve the likelihood of a positive outcome.
It is also important to seek help for a cannabis use disorder. A doctor or mental health professional can discuss the treatment options with the person.
NAMI notes that early treatment of psychosis, during either pre-psychosis or the first episode of psychosis, may provide the best outlook.
Psychotherapy and medications can help manage and reduce the effects of psychosis and schizophrenia symptoms.
A person needs to continue with treatment even after recovering from an acute episode of psychosis to prevent relapse.
Cannabis use may cause psychosis and other symptoms that affect mood and cognitive (thinking) function. The effects may disappear as the drug wears off.
In some people, consistent use of cannabis may cause symptoms of schizophrenia, particularly if they have a genetic predisposition to the condition.
Anyone who experiences any symptoms of psychosis needs to consult a healthcare professional as soon as possible. Early treatment can help improve outcomes and recovery.