RESEARCH QUESTION 1:
Changes in Mental Health Symptoms
Methods Notes: Eligible studies must report changes in symptom levels, proportion of participants above a cutoff threshold, or proportion of participants who change by a pre-defined magnitude (e.g., minimal clinically important difference) across a delineated COVID-19 related event. This could include comparisons of pre-COVID-19 and COVID-19 symptoms, symptoms at the initiation of the outbreak to the peak, or symptoms during highly restrictive isolation periods to subsequent periods, for instance. Studies with < 100 participants are excluded.
We are not including cross-sectional studies that report percentages of participants with scores above cutoff thresholds on commonly used symptom questionnaires. Conclusions that can be drawn from that type of data about mental health effects from COVID-19 and clinical implications, however, are limited, and, per our protocol, we have not included those studies. This is because percentages of people who score above a threshold on standardized questionnaires vary, sometimes dramatically, between populations, even in normal times. For example, the percentage of participants with scores of at least 10 on the Patient-Health Questionnaire-9, a commonly used measure of depressive symptoms, in large, randomly selected, regional or national general population samples, has been reported as 4% in Hong Kong (N = 6,028); 6% in Germany (N = 5,018); 7% in Shanghai, China (N = 1,045); 8% in the United States (N = 10,257); 8% in the province of Alberta, Canada (N = 3,304); 11% in Sweden (N = 3,001); and 22% in Jiangsu Province, China (N = 8,400). Even within populations from the same region, the percentage can vary dramatically depending on sample characteristics. In Jiangsu Province, for example, the percentage among rural residents (32%) is twice that of urban residents (16%); it is also several times higher for older adults (25% for 55-64 years; 87% for ≥ 65 years) than for young adults (8% for 18-34 years). Further complicating interpretation when there is not a time-based or other relevant comparator, percentages from symptom measures such as the PHQ-9 tend to dramatically overestimate prevalence that would be obtained from validated methods for ascertaining prevalence of mental health disorders, and there is too much heterogeneity between samples in the difference to correct for this statistically.
Summary of Results: Only one study, which included 209 undergraduate students from Switzerland, has reported mental health symptoms during COVID-19 compared to previously. In that study, symptoms of depression increased by 0.53 (0.33 to 0.72) standard deviations, stress by 0.40 (0.20 to 0.59), loneliness by 0.29 (0.10 to 0.49), and symptoms of anxiety by 0.17 (-0.02 to 0.37).
Comment: Among university students for whom social relationships are likely highly valued and for whom risk of complications from COVID-19 is generally lower than among other adults, symptoms of depression increased substantially more than anxiety. It will be important to understand to what degree this finding is replicated in other university students and whether anxiety is relatively more important in more vulnerable populations.
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*Abbreviations: CES-D= Center for Epidemiologic Studies Depression Scale; GAD-7= Generalized Anxiety Disorder; PSS= Perceived Stress Scale; ULS-9= University of California, Los Angeles (UCLA) Loneliness Scale