Factors Moderating the Association between Cannabis Use and Psychosis Risk: A Systematic Review

Abstract

Increasing evidence indicates a relationship between cannabis use and psychosis risk. Specific factors, such as determinants of cannabis use or the genetic profile of cannabis users, appear to moderate this association. The present systematic review presents a detailed and up-to-date literature overview on factors that influence the relationship between cannabis use and psychosis risk. A systematic search was performed according to the PRISMA guidelines in MEDLINE and Embase, and 56 studies were included. The results show that, in particular, frequent cannabis use, especially daily use, and the consumption of high-potency cannabis are associated with a higher risk of developing psychosis. Moreover, several genotypes moderate the impact of cannabis use on psychosis risk, particularly those involved in the dopamine function, such as AKT1. Finally, cannabis use is associated with an earlier psychosis onset and increased risk of transition in individuals at a clinical high risk of psychosis. These findings indicate that changing cannabis use behavior could be a harm reduction strategy employed to lower the risk of developing psychosis. Future research should aim to further develop specific biomarkers and genetic profiles for psychosis, thereby contributing to the identification of individuals at the highest risk of developing a psychotic disorder.

The Impact of Cannabidiol on Human Brain Function: A Systematic Review

“…Along these lines, CBD also showed opposite effects compared to THC during resting state and several cognitive paradigms in healthy volunteers. It is known that THC has pro-psychotic and anxiogenic properties, particularly evident with high potency cannabis strains (rich in THC) and at high doses ( Campeny et al, 2020 ; Van der Steur et al, 2020 ). Opposite neurophysiological effects were reported on prefrontal, striatal and limbic areas, which are relevant neural substrates of psychosis and anxiety, and during several cognitive processes, such as salience, verbal memory, response inhibition, emotional processing and auditory/visual processing.…”

The pharmacological interaction of compounds in ayahuasca: a systematic review

“…62 Consumption of either cannabis or ayahuasca alone can, in some cases, produce states of extreme anxiety, panic, or psychosis. 52,63,64 Umut et al 64 describes a case in which the subject developed psychotic symptoms immediately after consuming a mixture of DMT and cannabis, concluding that DMT worsened the symptoms of previous chronic cannabis use-induced mania. In one reported case, a combination of ayahuasca and cannabis resulted in a psychotic episode 65 in a subject with no history of psychosis.…”

Addictiveness: an independent dimension in the psychotic syndrome. Presentation of the Addictiveness in the Psychotic Syndrome Assessment Scale (APSAS)

“…This approach of clinical dimensionality would be compatible with the classic models of SUD-psychosis comorbidity that assume complex and bidirectional causal relationships, thus focusing on the diversity of substances that can modify dopaminergic neurotransmission (Wise & Robble, 2020). In these models, not only the intensity, frequency, temporal proximity of the last consumption of the substance or the behavioural and functional consequences of intoxication are important, but the age of onset of use has been shown to be a determining factor, at least in psychosis associated with cannabis use (van der Steur et al, 2020).…”