Engagement Dynamics in Online Mental Health Communities: The Role of Trust and Social Support in Young Adults’ Attitudes and Norms

Online Mental Health Communities (OMHCs) are becoming vital spaces for young people to access peer-based mental health support. However, the behavioral factors that influence continued participation in these communities remain underexplored. This study extends the Theory of Planned Behavior (TPB) by including initial trust, OMHC engagement, emotional support, informational support, and perceived anonymity to examine young users’ intentions to sustain their participation in OMHCs. Using Partial Least Squares Structural Equation Modeling (PLS-SEM), data from 459 Filipino youth aged 18 to 30 were analyzed to test the model. Results revealed that attitude, subjective norms, and perceived behavioral control significantly predict sustainable use intentions. Emotional and informational support strongly influenced subjective norms, while initial trust and OMHC engagement influenced attitude. Perceived anonymity, however, did not exhibit a significant effect. The findings suggest that trust, peer support, and user engagement play an important role in shaping participation in digital mental health spaces. The article concludes with practical implications for platform developers, mental health professionals, and policymakers who aim to improve access to mental health support online. By addressing the psychosocial dynamics shaping OMHC participation, the research advances the understanding of help-seeking behaviors in low-resource and collectivist settings. Plain Language Summary How trust and support affect young people’s involvement in online mental health communities Access to mental health resources is limited worldwide, especially for young adults in developing countries like the Philippines. This study examines what influences Filipino young adults to join and stay active in online mental health communities (OMHCs). Researchers surveyed 459 participants aged 18-30 and used a statistical model to find patterns in their behavior. We discovered that young people's continued use of OMHCs is influenced by their attitudes, the support they feel from others, and how much control they believe they have over their participation. Trust in the platform and feeling emotionally supported also helped shape positive attitudes. Interestingly, staying anonymous was not as important as expected. The study shows that feeling supported, engaged, and trusting the platform matters more than hiding one’s identity. These insights can help improve the design of mental health platforms and guide professionals and policymakers in making digital support more accessible, especially in places with limited mental health resources like the Philippines.