Smoking marijuana may increase ‘noise’ in a person’s brain
At high doses, cannabis use can produce brief psychotic reactions or acute psychosis in people who do not have schizophrenia. Researchers have found evidence of cannabis use leading to psychotic symptoms such as depersonalization, fears of dying, irrational panic and paranoid ideas, which quickly remit after the effects of marijuana dissipate.
Cannabis use can affect complex mental processes through its effects on neurotransmitters such as dopamine, gamma-aminobutyric acid (GABA) and glutamate transmission. Dysregulation in these neurotransmitters is also a factor underlying the etiology of psychotic disorders. Marijuana’s psychoactive constituent delta-9-tetrahydrocannabinol (THC) leads to increased randomness or task-irrelevant brain activity (i.e., “neural noise”) in patients with schizophrenia, according to a recent study published in the journal Biological Psychiatry.
The link between adolescent marijuana use and schizophrenia
Marijuana may raise a person’s risk for developing psychotic disorders (e.g., schizophrenia) and other mental disorders including anxiety and depression. However, the development of psychotic disorders varies considerably depending on the amount of marijuana used and the age at which the individual first used it. One study reported that patients with schizophrenia had an earlier onset of first episode psychosis when they had a history of cannabis use.
Other studies have suggested that schizophrenia and other psychotic disorders are more likely to develop in adulthood among adolescents who use marijuana, primarily if they are genetically vulnerable. Researchers have identified people with the C/C variant of the AKT1 gene as having seven times the risk of developing psychosis if they used marijuana on a daily basis compared to those who infrequently used or did not use marijuana. According to the National Institute on Drug Abuse (NIDA), the AKT1 gene codes for an enzyme that activates the release of dopamine in the striatum, an area of the brain that is involved in movement, motivation and reward. Coincidentally, altered dopamine signaling is known to be involved in the development of schizophrenia.
In addition, studies have found evidence for an increased risk of developing psychosis among adults with a specific variant for the enzyme catechol-O-methyltransferase (COMT). The COMT enzyme breaks down neurotransmitters such as dopamine and norepinephrine, which can increase the risk for schizophrenia and also worsen the course of schizophrenia in patients who already have the disorder present.
The impact of marijuana use on the development of psychotic disorders
The development of psychotic disorders such as schizophrenia is still widely misunderstood, although researchers have discovered functional and structural changes in the brain regions responsible for processing information, memory, perception, emotion and language among patients with psychotic disorders. Recent studies indicate that patients with schizophrenia and psychosis demonstrated increased randomness or noise in neural (i.e., brain) activity. In addition, evidence shows similar psychosis-like effects and brain abnormalities following the administration of THC and other brain cannabinoid receptor agonists as seen in schizophrenia.
Deepak Cyril D’Souza, M.D., from Yale University, and his colleagues investigated the ability of THC to induce psychotic symptoms and its relationship with neural activity in the brain. Not only did they find that marijuana increased development of psychotic-like positive and disorganized symptoms such as those seen in schizophrenia, but the researchers also found that greater neural noise was related to an increase in THC-induced psychosis-like symptoms, suggesting that increased neural noise following marijuana use may contribute to the onset of psychotic symptoms.
As the symptoms of schizophrenia and other psychotic disorders can be disabling, it is highly important to identify the mechanisms through which psychotic symptoms develop to reduce the impairment experienced among these individuals. The Sovereign Health Group provides evidence-based behavioral health treatment plans for patients with psychotic disorders, such as schizophrenia, and marijuana use disorders. For more information on our treatment programs, please contact our 24/7 helpline.
About the author
Amanda Habermann is a Content Writer for the Sovereign Health Group. Graduate of California Lutheran University, she received her M.S. in clinical psychology with an emphasis in psychiatric rehabilitation. Her master’s thesis was written on, “The effect of parental codependency on elementary school children’s social and emotional development,” and her research has been accepted for poster presentations at the Western Psychological Association. She brings to the team her extensive clinical background and skills in psychological testing and assessment, clinical diagnosis, research and treatment and recovery techniques for patients with mental illness. She is a passionate researcher and enjoys staying up to date on the newest topics in the field. For more information and other inquiries about this article, contact the author at firstname.lastname@example.org.