Statistical analysis
Descriptive analyses were performed for all variables. The Shapiro–Wilk
test was used to test the normal distribution of continuous variables.
We revised the analytical plan after the registration because of
differences in age and sex between the cohorts (see Table 1). A stepwise
regression controlling for these differences and involving a dummy code
to compare the behavior before and during quarantine (0 =before
quarantine, 1 = after quarantine) was conducted. To determine the
differences between the two groups (before and after quarantine) and
cohorts (data obtained from the first and second questionnaires), we
used the t-test, chi-square test, and Fisher’s exact test when
appropriate. Univariate and multivariate correlations were also
determined. We followed up with multiple regressions predicting
variables of interest and potential moderators (main effect and
interaction with COVID-19 stress) associated with COVID- 19 stress.
Categorical moderators were dummy-coded (i.e., sex: 0 = men, 1 = women).
Statistical Package for the Social Sciences (SPSS v25) was used for
statistical analysis, and a two-tailed p-value < 0.05 was
considered significant. Missing values were excluded from the analysis.