Substance induced psychosis among persons with concurrent mental health and substance use disorders under pandemic

Background

Most people have been affected by the COVID-19 pandemic with its restrictions and infection measures. Persons with co-occurring mental health and substance use disorders (MHD/SUD) who are already a marginalized group might be especially affected. Substance-induced psychosis (SIP) is a psychotic disorder that occurs during or relatively immediately after taking a drug, and which causes hallucinations, delusions and psychomotor disturbances. In this study, which is part of a larger project which explores the impact of the COVID-19 pandemic on persons with MHD/SUD, we aimed to study the occurrence of SIP among persons with MHD/SUD in the years 2019-2020.

Method

In this cohort study we merged data from the Norwegian Patient Register, the Norwegian Surveillance System for Communicable Diseases and census data from Statistics Norway. We identified 35.000 individuals who received a diagnosis of co-occurring MHD/SUD between the years 2019-2021. A graphical approach, logistic and cox regression models were used to examine SIP between the years 2019 to 2021 according to the consecutive COVID-19 waves during the first two years of the pandemic.

Results

We have identified 1705 persons who experienced 11743 episodes of any SIP during 2019 and 2021, without significant differences between the years. Any SIP were in all years more prevalent among men than in women. The most prevalent type of SIP in every year was caused due to multiple substances, followed by cannabis and amphetamine. Graphs based on descriptive analysis and logistic regression showed a significant trend in the incidence of SIP caused due cannabis and amphetamines. While there was a negative trend in cannabis SIP with the beginning of the pandemic, the incidence of amphetamine SIP was rising from March 2020. Cox regression showed a significant shorter hospitalisation time of persons with SIP during the first two pandemic years compared to 2019.

Conclusion

This preliminary results showed that the COVID-19 pandemic with its restrictions on populations level like closed boarders, the discharging of patients from long-term psychiatric treatment and shutdown of low-threshold places directed to persons with MHD/SUD might have affected the type of substances consumed by persons with MHD/SUD and how they have been treated by the health care services. There is reason to believe that new pandemics will emerge in the future. Therefore, it is crucial to gain knowledge on how vulnerable groups such as persons with MHD/SUD act in times emergencies, in order to deliver appropriate health care services in future.