Discussion
depression, anxiety
The main goal of this study was to evaluate the practicability of PoET and to examine whether PoET might be effective to promote mental health in the general population. We hypothesized an increase in positive mental health factors (Hypothesis 1) and a decrease in depression, anxiety, and stress symptoms (Hypothesis 2) in PoET participants one month after the second training day. For the control group, we hypothesized that there would be no changes in these scores (Hypothesis 3).Regarding the effectiveness of PoET, our results were mixed but definitely promising. Due to the fact that the groups were not randomly allocated, these findings should be handled with care.According to the first hypothesis, there was a descriptive increase in positive mental health factors assessed with the PMH in the PoET group, but the differences were not significant in the statistical analyses so that the hypothesis could not be confirmed with the present data. These results are in contrast to previous research: While we found no significant changes in PMH scores of the PoET group, other studies showed positive effects of positive psychology interventions on (psychological) well-being [In this regard, it is important to refer to possible reasons for the absence of significance: One of them could be the differences of the PoET and control group. Since the groups were not randomly assigned, they differed significantly in age (The second hypothesis could be partially confirmed with significant decreases of depression and anxiety symptoms assessed with the DASS-21 from T1 to T3. According to Cohen [Overall, these results indicate that PoET is effective to reduce symptoms of depression and anxiety in the general population. It is still to explore, whether an adjusted version of PoET might have similar effects in a clinical population. In the future, based on these promising results, PoET should be further examined and evaluated in a randomized controlled trial.According to the third hypothesis, there were no significant changes in the control group in neither of these measures, which suggests that the improvements in the PoET group can be attributed to the training itself and not to other possible environmental factors.In addition to the three hypotheses, we also examined possible increases in other relevant dimensions in the PoET group in comparison to the control. These were optimism, gratitude, resilience, happiness, and self-efficacy. Solid significant changes could only be found in optimism with a medium effect size [For the other constructs (gratitude, resilience, happiness, and self-efficacy), no significant effects were found, but all of them increased descriptively, indicating that there were slight improvements. Since other studies have shown that positive psychology interventions are able to enhance these constructs [Besides these promising results, the main goal of this study was to test PoET’s feasibility regarding the general concept and the training circumstances. Implementing PoET as a two-session online training was experienced to be feasible by the research team as well as participants. Beforehand, we had considered whether to conduct the training within one session, two sessions or more. Although past positive psychology intervention studies often used five or more training sessions [