Objectives: The conducted research had the following objectives: to examine the differences in anxiety, depression and stress between persons who had previously been treated with psychotherapy and persons who had not been treated with psychotherapy; to examine differences in the symptoms of PTSD between people who have previously been treated with psychotherapy and people who have not been treated with psychotherapy; finally, we aimed to examine the predictor significance of earlier psychotherapeutic treatment to the levels of depression, anxiety, and stress. Methods: The research was conducted online using self-assessment questionnaires during March and April 2020. The study involved 1234 participants, of whom 388 with mental disabilities. The average age was 39 years. The measurement instruments used to prove the hypotheses were the following questionnaires: 1. Depression, Anxiety and Stress Questionnaire (DASS), 2. PCL-5 Questionnaire for Assessing PTSD Symptoms and 3. General Data Questionnaire, which was prepared for the purposes of this study. Following methods of descriptive statistics were used: mean values, arithmetic mean, median, standard deviation and interquartile range as indicators of deviation from the mean. Participants were divided into two groups, a group of respondents with mental disabilities and a group of participants who did not report the existence of mental disorders. Difference in numerical values among the observed groups were analyzed using Mann-Whitney U test. Impact of psychotherapy on depression, anxiety, and stress (DASS) were examined by regression analysis. Results: The results of the study showed that the levels of anxiety, depression, stress and symptoms of post-traumatic stress disorder were significantly higher in subjects previously treated with psychotherapy than in untreated subjects. The predictor significance of previous psychotherapeutic treatment to higher levels of depression, anxiety, and stress was also determined. The results of the study confirmed all three research hypotheses. Conclusion: It was concluded that the group of subjects who were treated with psychotherapy showed a higher psychological load during the COVID-19 pandemic compared to the population that was never treated with psychotherapy.