Understanding the Link between Marijuana Use and Schizophrenia
In recent years, there has been growing evidence linking cannabis use, particularly heavy or prolonged use, to the development and worsening of schizophrenia symptoms, especially in adolescents and young adults who have a genetic predisposition to psychiatric disorders.
Key points supporting this link include:
- Genetic overlap: Large genetic studies reveal that cannabis use disorder (CanUD) shares common genetic variants with schizophrenia, especially variants near genes affecting brain nicotinic receptors (e.g., CHRNA2). This indicates a genetic predisposition linking cannabis-related problems with schizophrenia risk.
- Bidirectional risk and vulnerability: CanUD and schizophrenia increase the risk of each other, creating a feedback loop where cannabis use can worsen psychiatric outcomes in genetically vulnerable individuals.
- Adolescents and young adults at highest risk: Early and frequent cannabis use, particularly before age 25, is associated with higher risks of developing psychiatric conditions, including schizophrenia. Genetic predisposition combined with early cannabis exposure increases the likelihood of negative outcomes such as cannabis use disorder and psychosis.
- Cannabis-induced psychosis as a precursor: Cannabis use can trigger acute psychotic episodes, sometimes called cannabis-induced psychosis, which may precede or develop into chronic schizophrenia in about 7% of cases in young adults.
- Exacerbation of schizophrenia symptoms: In patients with schizophrenia, cannabis use is shown to worsen symptoms and increase relapse rates of psychosis.
- High potency and concentrates: Use of high-THC cannabis concentrates accelerates the risk and severity of mental health problems and cognitive decline, especially in genetically susceptible users, with earlier onset of dependence and schizophrenia-like symptoms.
In summary, evidence shows that cannabis use, particularly heavy use starting in adolescence or young adulthood, can increase risk and worsen schizophrenia symptoms in those with genetic vulnerability, mediated by shared genetic factors and neurobiological mechanisms affecting brain receptors and circuits.
Pre-psychosis symptoms, according to the National Alliance on Mental Illness (NAMI), 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, and a lack of feelings or very strong, inappropriate emotions. Anyone who experiences these symptoms or notices them in someone else needs to contact a doctor as soon as possible.
Treatment for psychosis or schizophrenia will include medications, such as antipsychotic drugs, and psychotherapy. Psychotherapy and medications can help manage and reduce the effects of psychosis and schizophrenia symptoms. Motivational enhancement therapy aims to motivate someone to use their internal resources to engage in treatment and create positive changes. Contingency management is an approach that involves frequent monitoring of the behavior that a person is working to change and provides incentives or rewards for positive changes.
Coordinated specialty care (CSC) may be an effective treatment for people in the early stages of psychosis, involving family support and education, psychotherapy, peer support, and support with education and employment. Cognitive behavioral therapy (CBT) is a type of psychotherapy that gives people strategies to identify and change negative patterns of thought and behavior.
The mind-altering component of cannabis is tetrahydrocannabinol (THC). Up to 25% to 30% of people who visit the emergency department due to cannabis use may experience symptoms such as anxiety, suicidal thoughts, and psychosis. It's crucial to remember that anyone experiencing these symptoms should seek immediate medical attention.
In conclusion, understanding the link between cannabis use and schizophrenia is essential to address the risks associated with cannabis use, particularly in adolescents and young adults. Early treatment of psychosis, during either pre-psychosis or the first episode of psychosis, may provide the best outlook. Anyone experiencing psychosis or pre-psychosis symptoms should not hesitate to contact a doctor as soon as possible.
- A genetic predisposition to psychiatric disorders, including schizophrenia, may be linked to cannabis-related problems due to shared genetic variants near genes affecting brain nicotinic receptors.
- Heavy or prolonged cannabis use, especially in adolescents and young adults, can increase the risk of developing psychiatric conditions such as schizophrenia, particularly for those with a genetic predisposition.
- Cannabis use can trigger acute psychotic episodes, known as cannabis-induced psychosis, which may precede or develop into chronic schizophrenia in about 7% of cases in young adults.
- In patients with schizophrenia, cannabis use is shown to worsen symptoms and increase relapse rates of psychosis.
- Use of high-THC cannabis concentrates can accelerate the risk and severity of mental health problems and cognitive decline in genetically susceptible users.
- Early treatment of psychosis, during either pre-psychosis or the first episode of psychosis, may provide the best outlook for those at risk, including those with a genetic predisposition to psychiatric disorders.
- In the health-and-wellness and mental-health fields, science continues to explore the predictive link between cannabis use and schizophrenia, highlighting the importance of preventative measures and early intervention strategies.
