Cannabis use as a potential mediator between childhood adversity and first-episode psychosis: results from the EU-GEI case–control study

Abstract

Background Childhood adversity and cannabis use are considered independent risk factors for psychosis, but whether different patterns of cannabis use may be acting as mediator between adversity and psychotic disorders has not yet been explored. The aim of this study is to examine whether cannabis use mediates the relationship between childhood adversity and psychosis. Methods Data were utilised on 881 first-episode psychosis patients and 1231 controls from the European network of national schizophrenia networks studying Gene–Environment Interactions (EU-GEI) study. Detailed history of cannabis use was collected with the Cannabis Experience Questionnaire. The Childhood Experience of Care and Abuse Questionnaire was used to assess exposure to household discord, sexual, physical or emotional abuse and bullying in two periods: early (0–11 years), and late (12–17 years). A path decomposition method was used to analyse whether the association between childhood adversity and psychosis was mediated by (1) lifetime cannabis use, (2) cannabis potency and (3) frequency of use. Results The association between household discord and psychosis was partially mediated by lifetime use of cannabis (indirect effect coef. 0.078, s.e. 0.022, 17%), its potency (indirect effect coef. 0.059, s.e. 0.018, 14%) and by frequency (indirect effect coef. 0.117, s.e. 0.038, 29%). Similar findings were obtained when analyses were restricted to early exposure to household discord. Conclusions Harmful patterns of cannabis use mediated the association between specific childhood adversities, like household discord, with later psychosis. Children exposed to particularly challenging environments in their household could benefit from psychosocial interventions aimed at preventing cannabis misuse.

The role of interpersonal trauma and substance use in mental health: A large population-based study

“…IPT is associated with risk of addictive behaviours ( Konkolÿ Thege et al., 2017 ), including alcohol ( Berenz et al., 2016 ; Shin et al., 2009 ; Thompson et al., 2008 ), tobacco ( Kuzminskaite et al., 2021 ; Shin, 2021 ), cannabis abuse ( Aas et al., 2014 ; Chu, 2012 ), and substance poly-abuse ( Hedtke et al., 2008 ; Schimmenti et al., 2022 ). These findings are observed in both general population ( Hicks et al., 2022 ) and clinical samples ( Trotta et al., 2023 ; Aas et al., 2014 ). Yet, the interplay between IPT, substance use, and mental health symptoms is still understudied.…”

“…For example, cannabis use may reduce depressive symptoms but increase psychotic symptoms in vulnerable individuals ( Di Forti et al., 2019 ; Feingold and Weinstein, 2021 ; Quattrone et al., 2019 ). Recent studies showed that the use of cannabis mediates the link between some traumatic events and the risk of psychosis ( Frydecka et al., 2020 ; Trotta et al., 2023 ) which suggest that for some individuals the impact of IPT on severe mental health symptoms is via cannabis use ( Frydecka et al., 2020 ; Trotta et al., 2023 ). Furthermore, the recent legalization of cannabis across western countries ( Di Forti, 2020 ) highlights the pivotal importance to understand the impact of substance use on mental health among vulnerable individuals.…”