Limitations
EMA
Our study is not without limitations: Only short scales were used in the EMA, which may be less reliable than other, more comprehensive questionnaires. Diagnostic information was collected via self-report, which may differ from clinical expert ratings or behavioral observations.There was no active control condition, so it was not possible to test whether AR or unspecific factors such as treatment expectations and regular contact with psychological trainers led to symptom improvements. However, compared with the control group, participants in the intervention group were more likely to consciously relax in daily life at post and follow-up, suggesting that the intervention led to behavioral changes that explain the intervention efficacy.Only one follow-up was conducted at 12 months, so nuanced symptom changes in the months after the intervention could not be examined. Additional follow-ups are also needed to evaluate the long-term efficacy after more than one year.The study was based on a convenient sample of adults aged between 18 and 55 and living in the Dresden area. Therefore, the present results may not be fully generalizable to other age and regional groups. Moreover, more women (68.6%) than men participated in the study, and many individuals (48.7%) did not provide EMA data at 12-month follow-up. At the same time, the intervention efficacy tended to be higher in women and individuals with more severe baseline symptoms, and more burdened individuals might have been more likely to skip the EMA at follow-up. Thus, one could speculate whether the intervention effects might have been overestimated. In this study, participants were given a smartphone to answer the EMA. In future studies, it may be useful to enable participants to conduct the EMA on their own smartphone to reduce the risk of dropout.