LAUSR

Dimitris and colleagues (2022;191(6):980-986) outline how the COVID-19 pandemic has put epidemiology under the spotlight, with mixed results. While epidemiological theory and methods have been critical in many successes, the ongoing global death toll from SARS-CoV-2 and the sometimes chaotic public messaging underscore that epidemiology as a field has room for improvement. Here, we use examples from psychiatric epidemiological studies conducted during the COVID-19 era to reflect on errors driven by overlooking specific major methodological advances of modern epidemiology. We focus on (i) use of non-representative sampling in online surveys, which limit the potential knowledge to be gained from descriptive studies and amplify collider stratification bias in causal studies; and (ii) failure to acknowledge multiple versions of exposures (e.g., lockdown, school closure) and differences in prevalence of effect measure modifiers across contexts, which cause violations of the consistency assumption and lack of effect transportability. We finish by highlighting (i) the heterogeneity of psychiatric epidemiological results during the pandemic across place and sociodemographic groups and over time; (ii) the importance of following the foundational advancements of modern epidemiology even in emergency settings; and (iii) the need to limit the role of political agendas in cherry-picking and reporting epidemiological evidence.