Randomization
Participants were randomly allocated to either the online self-help training (intervention) or CAU with an allocation ratio of 1:1, stratified by hospital. Block randomization (block size 10) was carried out through the sealed envelope system. Randomization was conducted by a researcher who was not otherwise involved in the study. The researchers had no influence on (and were blinded for) the randomization process. We used coding and separating personal data from the research data to anonymize the data [