Addressing Cannabis Psychosis and the Media
The article is intended to provide guidance and discussion points on the recent media coverage around cannabis and psychosis. Phil Molloy, MD, is a contributor to this blog post. It originally appeared here and is an updated version of this post about psychosis
The debate surrounding Cannabis and its potential link to psychosis is reinvigorated by a recent article in The Wall Street Journal, reporting on an 18-year-old male who suffered a psychotic episode requiring hospitalization following cannabis use.(1) That was then followed by another WSJ article criticizing the risk assessment of Cannabis released by HHS. This 2nd WSJ article reported on a 32-year-old female with no history of mental illness who was diagnosed with “cannabis-induced psychosis” after fatally stabbing her boyfriend, she then stabbed her dog and herself.(2) The take home message, discussed in detail below, is that despite the public perception of cannabis-products being relatively safe and free of serious side effects, Healthcare Providers (HCPs) need to be aware of this association and screen patients with (or at risk of) psychosis for cannabis use, provide education or counseling to them, and their family, as appropriate.
This topic is multifaceted and complex, the central question is whether Cannabis use leads to psychosis, or if it’s the other way around. There is emerging consensus that there's an association between marijuana and psychosis. Of all the risky conditions "known" to be associated with Cannabis (i.e., adverse events) psychosis/schizophrenia is perhaps the best established. A look at the scientific literature and news coverage over the years makes this association clear, despite imperfect methodologies. There will never be a randomized controlled trial (RCT), and there are issues with animal models looking at mental health and cannabinoids. Hence, the causal nature of this relationship remains a subject of debate. Some argue that the rising global rates of Cannabis use should correlate with similar increased rates of psychosis, this perspective may oversimplify a complex issue.
Genome-wide association studies (GWAS) offer a unique lens into this debate. If Cannabis or THC directly caused schizophrenia, we would expect to find specific genetic markers tied to both. However, the reality is more nuanced. A2022 editorial by Ganesh et al.,(3) elucidates that while Cannabis use may increase psychosis risk, and the argument is that it is neither a necessary nor a sufficient cause. This suggests the presence of multiple causal components, challenging the idea of a straightforward cause-and-effect relationship. As Ganesh et al., stated,
"While cannabis use may increase the risk for psychosis, its exposure is neither necessary nor sufficient for psychosis, suggesting that is one of multiple causal components. Furthermore, the criterion of temporality fails to account for possible underlying reverse-causal or confounding effects of genetic risk that predates cannabis exposure."
The data limitations in this area are significant. Most studies focus on ‘lifetime cannabis use’ without delving into the specifics – the source or type of the Cannabis-product used. This general approach falls short in providing the nuanced data needed for informed policymaking. We need to understand which specific products and factors are linked to these risks. One part of the solution may be improving access to and engagement with platforms for individuals to report undesirable effects or adverse effects of THC-containing products.
However, we do know a few key factoids:
The use of cannabinoid-containing products has increased
The incidence of psychosis in the US is increasing
The cannabis/psychosis effect is likely associated with THC exposure, with some evidence of a dose response effect
While extracts like hashish have been available since ancient times, access to high-THC products has increased recently, both in regulated and unregulated markets
There are some prospective studies showing that severe cannabis use disorder (CUD) or problematic drug use increases the risk for psychosis
Heather Bacchus, a parent interviewed by the Wall Street Journal, poignantly captures the essence of this issue: "I didn’t know that marijuana could cause paranoia. They don’t even know what they’re smoking." Her words underscore the gap in public awareness and the pressing need for more informed discussions on Cannabis use and its implications.
So, what should HCPs conclude from this? It is presently reasonable to conclude that Cannabis use increases the risk of psychosis in vulnerable “at risk” persons. The well-done analysis of this by Livne (4) et al states: “A prudent conclusion appears to be that part of this relationship is causal.” HCPs are advised to get comfortable in having non-judgmental conversations with their patients about Cannabis use. For those using or considering using, consider the person’s potential risk for adverse experiences, specifically those at risk for psychosis. Many current guidelines and reviews have concluded that Cannabis us is contraindicated in such patients, including those with strong family histories of psychosis or schizophrenia.
References (hyperlinked in text above)
1. WSJ Jan 10, 2024. “More teens who use marijuana are suffering from psychosis”
2. WSJ Jan 21, 2024. “Marijuana is more dangerous than Biden’s HHS lets on”
3. Ganesh S, D’Souza DC. “Cannabis and Psychosis: Recent Epidemiological Findings Continuing the ‘Causality Debate’” Am J Psychiatry 2022(Jan);179:8-10
4. Livne O, et al. “Association of cannabis use-related predictor variables and self-reported psychotic disorders: US adults, 2001-2002 and 2012-2013” Am J Psychiatry 2022(Jan);179:36-45
