Predicting suicide rates during the COVID-19 pandemic using a pre-pandemic death rate model

In 1952, the psychiatrist Erwin Stengel hypothesized that suicide becomes rarer in times when the value of life within a society is lower, when death is more common. In Canada, suicide rates and death rates present with consistent seasonal patterns between years. However, these were broken by the high death rates occurring at unusual times of year during the COVID-19 pandemic. This offers a unique opportunity to observe whether suicide rates follow suit. The present study models weekly Canadian suicide rates using death rates, from time series data spanning 2010 to 2019 (n = 521). Results indicate that suicide rates decrease on average by 0.27 standard deviations per 1 standard deviation increase in the death rate. This model is then used to predict 2020 suicide rates, using 2020 death rates (n = 52). These predictions account for 11.6% of the variation in actual 2020 suicide rates. However, this model does not perform well when predicting 2021 suicide rates. Limited evaluation of incomplete data from 2022 and 2023 was carried out as additional validation. We conclude that the process co-generating suicide and death rates pre-pandemic was maintained during the pandemic in 2020, but was disrupted in 2021.