In young adults prone to psychosis, a reduction in brain connectivity has been observed, a dysfunction that cannabis use appears to aggravate, according to a new study. This discovery could allow the development of treatments targeting psychotic symptoms on which current medications do not act.
As part of a first-of-its-kind study, a research team from McGill University found that density synaptic activity was significantly weaker in people at risk of psychosis than in healthy subjects in the control group. The synapse is the area located between two neurons and ensuring the transmission of information from one to the other.
“Psychosis does not threaten all cannabis users, but for some, the risk is high. Our work sheds light on the causes of this high risk,” explains Dr. Romina Mizrahi, lead author of the study and professor at the Department of Psychiatry at McGill University.
“It appears that cannabis disrupts the natural mechanism of synaptic strengthening and pruning, which is essential for the development of a healthy brain.”
Avenues for developing new treatments Using cutting-edge brain imaging technology, the team studied 49 people aged 16 to 30, some of whom had recent symptoms of psychosis or were considered as high risk. Published in JAMA Psychiatry, the study results indicate that low synaptic density is associated with social withdrawal behavior and a lack of motivationdisorders difficult to treat, specify the scientists.
“The vast majority of current medications target hallucinations, but do not treat the symptoms that complicate interactions in society, at work or at school,” says Belen Blasco, lead author of the study and doctoral student in the Integrated Program in neuroscience from McGill University. “Research into synaptic density could lead to the development of treatments capable of improving patients’ social competence and quality of life.”
We already knew that cannabis was a risk factor for psychosis, even schizophrenia, but thanks to this study, a research team managed to measure for the first time, in real time, structural changes in the brains of people with high risk.
The next step for the research team will be to determine whether the observed changes could predict the occurrence of psychotic disorders, and possibly intervene before symptoms appear.
The study was conducted at the Douglas Mental Health University Institute and the Neurological Institute-Hospital of Montréal from McGill University, and was funded by the Canadian Institutes of Health Research.
Reference:
The article “Synaptic Density in Early Stages of Psychosis and Clinical High Risk,” by Belen Blasco, Kankana Nisha Aji, Romina Mizrahi et al., was published in JAMA Psychiatry.
