Participants were volunteers, recruited online between 30 March and 6 April 2020, using a snowballing technique. The initial sample included 54,245 Internet users from 27 countries and areas who participated in the COVIDiSTRESS study. However, based on the reliability analysis, we decided to exclude one country (Kosovo). The final sample consisted of 53,524 participants from 26 countries and areas (see the Results section for more details). Participation was not remunerated. The numbers for each country with their respective individualism scores (based on the Hofstede index; Hofstede, 2001; Hofstede et al., 2010), along with detailed descriptions of all participants from each country are presented in the Supplementary Material, Table S1 (https://osf.io/cznr8/). As stated in the pre‐registration, we only included countries and areas with N > 300 participants.