When asking ‘how are you?’ may not be enough: The relationship between stress and alcohol use

The onset of the COVID-19 pandemic was accompanied by an increase in alcohol use in a third of the population worldwide. As alcohol use is the greatest risk factor for premature death in people ages 15 to 49, it is important to understand its predictors. To date, the literature shows that subjective stress predicts increased alcohol use. However, no studies have investigated the effect of physiological stress (via the stress hormone cortisol) on alcohol use during the pandemic. This study aimed to identify the predictive value of cortisol and subjective stress on alcohol use over the course of a long-lasting stressor (COVID-19 pandemic). Every three months, between June 2020 and March 2021, 94 healthy adults (ages 19-54) answered questionnaires assessing alcohol use. In June, participants reported pre-pandemic alcohol use, subjective stress measures, and provided a hair sample. The latter allowed us to quantify the cumulative levels of cortisol produced in the three months prior to and following the start of the mandatory lockdown in March 2020 in Quebec, Canada. While controlling for sex, age, and pre-pandemic cortisol levels, multilevel linear regressions revealed a triple interaction between time, pandemic-related cortisol levels, and subjective stress. Analyses revealed that alcohol use increased only among people with concomitant high subjective stress and high pandemic-related cortisol concentrations. Moreover, this increased alcohol use remained elevated one year later. This study documents the importance of simultaneously considering subjective and physiological stress systems to identify people at risk of increasing their alcohol use during the pandemic.