Abstract This prospective study aimed to examine changes in mental health and differences due educational status (ES) country among young adults aged 20-40 from four countries during the COVID-19 pandemic a three-month period. The total of 1714 participants (932 women): students ( n = 321) non-students 519) 20-30, educated 388), non-educated 486) 31-40 Poland 445), Slovenia 430), Germany 417), ...