Can cannabis mess with your brain’s natural wiring? A new study suggests this may be the case, especially for young adults who are already at risk for psychosis. We are talking about a critical period in brain development when connections between neurons are fine-tuned, and it turns out that cannabis can interfere with those functions.
A study published in JAMA Psychiatry highlights how cannabis use may reduce brain connectivity in young adults at risk for psychosis. The study, conducted by researchers at McGill University, found that individuals at high risk for psychosis had decreased synaptic density – connections between neurons – compared to healthy controls. These findings shed light on how cannabis may interfere with brain development and may provide new directions for understanding and treating psychological disorders.
disrupted brain development and psychosis
Psychosis, which includes conditions such as schizophrenia, typically emerge during adolescence or early adulthood, a critical period for brain development. During this time, the brain undergoes synaptic pruning, a natural process that eliminates weak synaptic connections to increase efficiency. Disruption of this process has been linked to psychosis. This study is one of the first to directly demonstrate synaptic deficits in people at risk for mental disorders.
Cannabis use has long been associated with an increased risk of psychosis, with frequent users experiencing higher susceptibility. However, the biological mechanisms underlying this relationship remain unclear. The research identified reduced synaptic density in critical areas of the brain, such as the prefrontal cortex, anterior cingulate cortex, and striatum—areas essential for cognitive and emotional functioning. These deficits were seen not only in individuals with psychosis, but also in those at high risk for the disorder before full symptoms emerge.
The study also found that cannabis use exacerbated these deficits, particularly during adolescence and early adulthood, a period of brain maturation. The striatum, an area associated with motivation and reward processing, showed the largest effect. This disruption in brain connectivity may help explain the increased risk of psychosis among cannabis users.
negative symptoms of psychosis
Negative symptoms of psychosis, such as social isolation and lack of motivation, were strongly associated with reduced synaptic density. These symptoms are extremely challenging to treat with existing drugs, highlighting the importance of addressing synaptic dysfunction. Interestingly, the study did not find a similar relationship between synaptic density and positive symptoms such as hallucinations, suggesting different mechanisms for different symptom domains.
The findings open several promising avenues for future research. An important question is whether interventions, such as cannabis cessation, can reduce these brain changes or delay the onset of psychosis. Additionally, the development of treatments specifically targeting synaptic dysfunction may address the unmet needs of individuals with severe negative symptoms, providing new hope for improved outcomes and quality of life.
While not everyone who uses cannabis develops psychosis, the study raises significant concerns about its effects on brain development, especially for individuals who are already at risk. Researchers emphasize the need to understand why some individuals are more sensitive to these effects than others.
