PURPOSE: The COVID-19 pandemic affected both substance use patterns and impacted healthcare systems. Substance-induced psychosis (SIP) is a severe mental disorder characterized by severe psychosis triggered by substance use. The number of treated SIP episodes may be sensitive to both changes in substance availability and treatment access. We study investigated whether the monthly prevalence of SIP episodes and mortality among SIP patients changed during the pandemic in Norway, comparing observed cases during 2020-2021 to predictions based on pre-pandemic trends. METHODS: We analyzed data from the Norwegian Patient Registry (2012-2021), we identified 7,150 individuals diagnosed with SIP (ICD-10 F1x.5). Monthly prevalence rates for overall SIP episodes and substance-specific SIP diagnoses (i.e., due to alcohol, cannabis, amphetamines, or multiple substances) and yearly mortality rates were predicted using ensemble time-series models. Deviations during the pandemic were assessed against 95% prediction intervals derived from pre-pandemic data. RESULTS: The observed monthly prevalence of episodes of any SIP during 2020-2021 largely matched predictions, with some deviations. Alcohol-induced psychosis showed lower than expected rates in 2020 but higher in 2021. Cannabis-induced psychosis rates were below expectations. Amphetamine-induced psychosis and psychosis due to multiple substances showed higher-than-expected rates during lockdowns, with lower rates between lockdowns. Mortality rates among SIP patients for all-cause mortality, suicide, and accidental poisoning during the pandemic were similar to those in the pre-pandemic period. CONCLUSIONS: The pandemic did not seem to alter the overall number of SIP episodes. There were, however, some drug-specific changes. This may reflect drug availability, changes in substance use, or changes in healthcare access. A high mortality burden was observed among patients with SIP. However, mortality rates due to all causes, suicide, and accidental poisoning in this group were similar in the pandemic and pre-pandemic periods.
Bramness et al. (Mon,) studied this question.