Cannabis isn’t ‘safer’ in your 20s and 30s – it’s linked to an earlier onset of psychosis

A new study published in the journal Biological Psychiatry suggests that cannabis use in one's 20s and 30s may lead to earlier onset of psychosis, challenging the notion that delaying cannabis use until the mid-20s is a safer option. Researchers analyzed 149 studies involving over 71,000 people over the past 15 years and found that cannabis use was associated with an earlier age of psychosis onset by an average of 2.5 years.

The impact was more severe for later-onset psychosis, with cannabis users who developed psychosis in their late 20s experiencing a 4.4-year earlier onset on average. This difference increased to more than 6.3 years for those who developed psychosis at age 30 or older. Earlier onset of psychosis is linked to worse clinical outcomes, greater functional impairment, and struggles with self-care, resulting in a loss of years that could have been spent pursuing education, building a career, traveling, starting a family, and forming strong relationships and support networks.

While the study found no evidence of earlier onset of psychosis for individuals who developed it before the age of 20, researchers suggest that a cumulative effect of cannabis as a brain toxin could be a contributing factor. More research is needed to understand the biological mechanisms behind these associations and the impact of different cannabis products and usage methods.