ABSTRACT
BACKGROUND: The COVID-19 pandemic, and the restrictions required to halt spread of the infection, are associated with increased population burden of moderate to severe symptoms of depression and anxiety. The aim was to quantify the mental health burden of the most severe COVID-19 related restrictions. METHODS: A natural experiment in which differences between Australian states and territories in the severity of restrictions for pandemic control, divided the population. People in Victoria experienced the most severe, and people in all other states and territories less severe or negligible restrictions. Data were collected in national, anonymously completed, online surveys (in April and in July / August 2020) of adults in Australia. Outcomes were, in the previous fortnight, experiencing clinically significant depressive symptoms (Patient Health Questionnaire 9 score ≥10); or symptoms of generalised anxiety (Generalised Anxiety Disorder Scale 7 score ≥10). RESULTS: In total, 23,749 eligible respondents contributed complete data. There were no differences in the population burden of mental health problems between Victoria and the other states and territories at Survey One. By Survey Two prevalence rates of clinically significant depressive (Adjusted Odds Ratio (aOR) 1.96; 95% CI 1.62; 2.37) and anxiety (aOR 1.87; 95%CI 1.53; 2.29) symptoms were substantially and significantly higher in Victoria than in other states and territories. LIMITATIONS: Online surveys are less accessible to some groups of people. The data are self-report and not diagnostic. CONCLUSIONS: The most severe COVID-19 restrictions are associated with near double the population prevalence of moderate to severe depressive and generalised anxiety symptoms.