Cannabis-induced psychosis decreased during COVID while stimulant-induced psychosis rose among Norwegian patients
During the COVID-19 pandemic in Norway, cannabis-induced psychosis episodes declined while amphetamine and poly-substance psychosis increased, and patients who experienced recurrent episodes were more likely to have psychosis triggered by different substances.
Quick Facts
What This Study Found
Despite fewer individuals being diagnosed with substance-induced psychosis (SIP) during COVID, total SIP episodes increased. Cannabis-induced psychosis declined while amphetamine- and multi-substance-induced psychosis rose. Patients with recurrent episodes were 50% more likely in 2020 (RR 1.50) and 30% more likely in 2021 (RR 1.30) to have psychosis induced by different substances than in 2019.
Key Numbers
Norwegian Patient Register 2019-2021; fewer SIP patients but more episodes during COVID; cannabis-induced psychosis declined; amphetamine/multi-substance SIP increased; recurrent SIP by different substances: RR 1.50 (2020) and 1.30 (2021) vs 2019
How They Did This
Retrospective cohort study analyzing data from all individuals with comorbid mental health and substance use disorders registered in the Norwegian Patient Register (2019-2021). Poisson regression and Sankey diagrams examined SIP occurrence, risk, and substance trajectories.
Why This Research Matters
The shifting patterns of substance-induced psychosis during the pandemic likely reflect changes in drug availability and pricing, demonstrating how supply-side disruptions affect clinical presentations.
The Bigger Picture
The finding that drug supply disruptions during COVID shifted which substances caused psychosis highlights the vulnerability of people with dual diagnoses to market-level changes they cannot control.
What This Study Doesn't Tell Us
Register-based data depends on clinical coding accuracy; cannot determine individual substance use patterns directly; pandemic effects on healthcare access may have reduced SIP diagnoses rather than actual cases; Norway-specific drug markets may not generalize
Questions This Raises
- ?Did the decline in cannabis-induced psychosis reflect reduced cannabis availability or reduced help-seeking?
- ?What happens to psychosis patterns when drug markets return to pre-pandemic norms?
Trust & Context
- Key Stat:
- Cannabis psychosis declined; stimulant psychosis rose during COVID
- Evidence Grade:
- National registry data covering all diagnosed cases, though limited by clinical coding accuracy and inability to separate healthcare access changes from true incidence changes.
- Study Age:
- 2024 study analyzing 2019-2021 data
- Original Title:
- Frequency and patterns of substance-induced psychosis in persons with concurrent mental health and substance use disorders during the COVID-19 pandemic: A Norwegian register-based cohort study.
- Published In:
- European psychiatry : the journal of the Association of European Psychiatrists, 67(1), e82 (2024)
- Authors:
- Leonhardt, Marja, Bramness, Jørgen G(4), Rognli, Eline Borger(2), Lien, Lars
- Database ID:
- RTHC-05467
Evidence Hierarchy
Watches what happens naturally without intervening.
What do these levels mean? →Frequently Asked Questions
How did COVID affect substance-induced psychosis?
Fewer people were diagnosed with substance-induced psychosis during the pandemic, but those who were diagnosed had more episodes. Cannabis-induced psychosis specifically declined, while episodes caused by amphetamines and multiple substances increased.
Did people switch between substances?
Yes. Among people who had recurrent psychotic episodes, they were significantly more likely to have episodes triggered by different substances during the pandemic compared to 2019 (50% more likely in 2020). This may reflect drug supply disruptions forcing users to switch substances.
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Cite This Study
https://rethinkthc.com/research/RTHC-05467APA
Leonhardt, Marja; Bramness, Jørgen G; Rognli, Eline Borger; Lien, Lars. (2024). Frequency and patterns of substance-induced psychosis in persons with concurrent mental health and substance use disorders during the COVID-19 pandemic: A Norwegian register-based cohort study.. European psychiatry : the journal of the Association of European Psychiatrists, 67(1), e82. https://doi.org/10.1192/j.eurpsy.2024.1797
MLA
Leonhardt, Marja, et al. "Frequency and patterns of substance-induced psychosis in persons with concurrent mental health and substance use disorders during the COVID-19 pandemic: A Norwegian register-based cohort study.." European psychiatry : the journal of the Association of European Psychiatrists, 2024. https://doi.org/10.1192/j.eurpsy.2024.1797
RethinkTHC
RethinkTHC Research Database. "Frequency and patterns of substance-induced psychosis in per..." RTHC-05467. Retrieved from https://rethinkthc.com/research/leonhardt-2024-frequency-and-patterns-of
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.