New Study Challenges Link Between Cannabis Use and Psychosis in High-Risk Individuals
A recent study published in the journal Psychiatry Research has challenged the commonly held belief that cannabis use is associated with an increased risk of developing psychosis in high-risk individuals. The study, titled Recreational Cannabis Use Over Time in Individuals at Clinical High Risk for Psychosis: Lack of Associations with Symptom, Neurocognitive, Functioning, and Treatment Patterns, explored the effects of regular cannabis use on teens and young adults who are at risk of developing psychotic disorders.
Conducted by a team of researchers from Zucker Hillside Hospital, Stanford University School of Medicine, University of Michigan, and University of California at Davis, the study discovered that over a two-year period, regular cannabis use did not trigger an early onset of symptoms. Surprisingly, the researchers even found a correlation between cannabis use and modest improvements in cognitive functioning, as well as a reduction in the use of other medications.
The study abstract acknowledges the inconsistent conclusions of previous research on the relationship between cannabis use and the onset of psychosis among high-risk individuals. The authors stated, Recreational cannabis use has recently gained considerable interest as an environmental risk factor that triggers the onset of psychosis. To date, however, the evidence that cannabis is associated with negative outcomes in individuals at clinical high risk (CHR) for psychosis is inconsistent.
To delve deeper into this correlation, the researchers tracked 210 CHR patients aged 12-25 who participated in an Early Detection and Intervention for the Prevention of Psychosis Program (EDIPPP). The mean age of the participants was 16.54. Over the course of two years, the mental health and prescription usage of regular cannabis users were compared to non-users.
The findings revealed that cannabis usage was not linked to the onset of psychosis. Additionally, a correlation was observed between cannabis use and positive symptoms when compared to non-users. The researchers stated, In summary, continuous cannabis use over 2-years of follow-up was not associated with an increased psychosis transition rate, and did not worsen clinical symptoms, functioning levels, or overall neurocognition. Nevertheless, our findings suggest that continuously using cannabis may be associated with slightly elevated, albeit non-significant, attenuated positive symptom levels relative to non-users.
It is crucial to note that this study was not intended to endorse cannabis use among youth or promote cannabis as a therapeutic tool for those at risk of psychosis. Instead, it contributes to the growing body of literature on the complex relationship between cannabis and psychosis.
Several recent studies have echoed the findings of this research. In a 2022 study published in the Canadian Journal of Psychiatry, an analysis of emergency room data revealed that Canada’s legalization program did not lead to significant changes in cannabis-induced psychosis or schizophrenia ED presentations. Similarly, a study published in the Journal of the American Medical Association in January 2023 found no association between state policies legalizing cannabis and psychosis-related outcomes in the United States.
However, it is worth mentioning that some studies have claimed a correlation between cannabis use and the onset of psychosis. Critics of cannabis legalization have long argued that high-THC cannabis can trigger schizophrenia and other severe mental health symptoms.
NORML’s Paul Armentano suggests that cautionary statements about cannabis, while less sensational, resemble the fear tactics used during the reefer madness era of the 1920s and ’30s. Armentano emphasizes that acute cannabis-induced psychosis is rare and typically occurs in individuals predisposed to psychosis or with pre-existing psychiatric disorders. Overemphasizing the potential risks of cannabis or advocating for re-criminalization may not effectively protect vulnerable populations. Instead, he recommends implementing regulated markets that restrict access to young people, providing clear warnings to specific vulnerable groups, and prioritizing consumer education to promote public health and minimize risks.
In conclusion, the recent study challenging the link between cannabis use and psychosis in high-risk individuals adds more complexity and nuance to the ongoing debate. While the study found no evidence of cannabis triggering psychosis in this particular population and even identified potential cognitive benefits, it is crucial to consider diverse perspectives and conduct further research to fully understand the relationship between cannabis and mental health outcomes.
