Cannabis use and psychosis are linked, but study finds age matters
Cannabis-users who develop psychosis for the first time in their 30s experience symptoms more than six years earlier than people with the condition who don't use the drug, according to new research.
A new study conducted by Australian researchers reveals that the onset of psychosis in individuals who use cannabis typically occurs 2.5 years earlier than in those who do not. This research, published in Biological Psychiatry, examined data from 149 international studies involving over 71,000 people. The study's senior author, Matthew Large from the University of New South Wales, emphasizes the importance of understanding the age-related impact of cannabis use on psychosis onset, as previous studies have suggested an association but lacked detailed analysis of age sub-groups.
The findings indicate that individuals who use cannabis often experience psychosis symptoms about 1.6 years earlier than non-users during their early 20s, but notably, those who begin using cannabis in their late 20s or older show symptoms an average of 6 years earlier than non-users. This suggests that the risk of developing psychosis due to cannabis use is more prominent in adults aged 30 and above, contradicting the common belief that early adolescent use is the primary risk factor.
Lead author Carly Stevens from UNSW highlights that while the adolescent brain is vulnerable to cannabis-induced neurodevelopmental disruptions, the cumulative impact of prolonged cannabis use may lower the threshold for early psychosis onset later in life.
Dr. Large, who works directly with patients, notes that approximately 3 percent of people will experience psychosis at some point, with 1 percent developing schizophrenia, a lifelong condition. The study's results are consistent with earlier findings, reinforcing the conclusion that cannabis use is associated with an earlier onset of psychosis.
Meanwhile, research fellow Jack Wilson from the University of Sydney stresses the growing evidence linking cannabis use to an increased risk of psychosis, especially with the availability of increasingly potent products in Australia. He points out that higher THC consumption is linked to greater harm risks, underscoring the need for caution regarding potency and usage frequency.
However, Stevens reminds that younger individuals are not entirely immune to cannabis-related harms. While early use can still pose risks, particularly neurodevelopmental impacts before the age of 25, the study's findings underscore that older adults who use cannabis face a higher risk of psychosis onset. Both researchers call for enhanced public health messaging and warnings about the potential harms of cannabis, especially given the increasing potency of available products.
They advocate for delaying cannabis use, particularly for adolescents, and avoiding high THC content to mitigate the risk of psychotic disorders.
Written by urgent.news from ABC News AU's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
