A new 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” published in the journal Psychiatry Research, examined teens and young adults at risk of developing psychotic disorders.
Conducted by a team of researchers at Zucker Hillside Hospital, Stanford University School of Medicine, University of Michigan and University of California at Davis, the study found that regular cannabis use over a two-year period did not trigger early onset of symptoms. Rather, the research actually found that it was associated with modest cognitive functioning improvements and reduced use of other medications.
Cannabis and Psychosis: Is There a Link for High-Risk Individuals?
In the study abstract, authors note the varying conclusions in the current body of research surrounding cannabis use and triggering the onset of psychosis among high risk individuals.
“Recreational cannabis use has recently gained considerable interest as an environmental risk factor that triggers the onset of psychosis,” the authors wrote. “To date, however, the evidence that cannabis is associated with negative outcomes in individuals at clinical high risk (CHR) for psychosis is inconsistent.”
To examine the correlation, researchers tracked 210 CHR patients aged 12-25 who participated in an Early Detection and Intervention for the Prevention of Psychosis Program (EDIPPP), with a mean age of 16.54 among the pool. Researchers compared the mental health and prescription usage of those who regularly consumed cannabis to non-users over the two-year period.
Researchers found that cannabis usage was not linked to the onset of psychosis, and they also saw a correlation between cannabis use and positive symptoms when compared to non-users.
Cannabis Use Lacks Psychosis Correlation, May Improve Some Functions
“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,” researchers stated.
“CHR youth who continuously used cannabis had higher neurocognition and social functioning over time, and decreased medication usage, relative to non-users,” they continued. “Surprisingly, clinical symptoms improved over time despite the medication decreases.”
The study was not meant to support cannabis use among youth or cannabis as a therapeutic tool for those at psychosis risk. Rather, it’s meant to add to the growing, and often polarizing, collection of literature on cannabis and psychosis.
A number of recent studies have affirmed the findings of this research. A 2022 study published in the Canadian Journal of Psychiatry analyzed emergency room data related to cannabis-induced psychosis, finding that Canada’s legalization program “was not associated with evidence of significant changes in cannabis-induced psychosis or schizophrenia ED presentations.”
Another study published in January 2023 in the Journal of the American Medical Association considered the same question as it pertains to the United States. Researchers came to the same conclusion: “The findings of this study do not support an association between state policies legalizing cannabis and psychosis-related outcomes.”
An April 2023 study similarly looked to examine the association between cannabis use and psychotic disorders in high-risk patients. They ultimately found, “There was no significant association between any measure of cannabis use at baseline and either transition to psychosis, the persistence of symptoms, or functional outcome.” They added that the findings “contrast with epidemiological data that suggest that cannabis use increases the risk of psychotic disorder.”
A New Version of Old Scare Tactics?
This is in contrast to a number of studies that have claimed cannabis, in fact, is correlated with the onset of psychosis. And opponents of cannabis legalization have claimed that high-THC cannabis can trigger schizophrenia and other extreme mental health symptoms since reform first hit the lips of legislators.
A recent op-ed from NORML’s Paul Armentano suggests that today’s warnings, albeit less sensational, mirror the reefer madness scare tactics of the 1920s and ‘30s, implying that cannabis smoking would lead to “incurable insanity,” among other claims.
“In reality, acute cannabis-induced psychosis is rare, and those who experience it are typically either predisposed to psychosis or have a pre-existing psychiatric disorder,” Armentano writes. He recognizes that those with certain psychiatric disorders may have a greater likelihood of experiencing adverse events after using cannabis, “sensationalizing the potential risks of cannabis will do little to protect them. Calling for the re-criminalization of cannabis in state-legal markets won’t either.”
“Rather, the establishment of a regulated market designed to keep cannabis products away from young people, and that provides clear warnings to those specific populations who may be more vulnerable to its effects—coupled with a policy of consumer education—is the best way to protect public health and mitigate consumers’ risks.”