**5. Conclusions**

Our population−based study indicated that PSU was associated with higher odds of severity of anxiety and depression symptoms and lower levels of mental well−being. The associations of PSU with impaired mental well−being outcomes could remain in people who screened negative for anxiety or depression symptoms. Such findings highlighted the importance to investigate other psychological constructs with PSU, particularly from aspects of positive psychology. Longitudinal and experimental studies are warranted to explain causality and possible mechanisms of the associations between PSU and mental health.

**Author Contributions:** Conceptualization, M.P.W., S.Y.H., C.S., S.S.-C.C., and T.H.L.; Formal analysis, N.G.; Funding acquisition, T.H.L.; Methodology, M.P.W., S.Y.H., C.S., and T.H.L.; Supervision, M.P.W. and S.Y.H.; Writing—original draft, N.G.; Writing—review & editing, N.G., T.T.L., S.Y.H., J.J.L., C.S., J.O., T.H.L., and M.P.W. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by the Hong Kong Jockey Club Charities Trust as part of the project: "FAMILY: A Jockey Club Initiative for a Harmonious Society" (https://www.family.org.hk/en).

**Acknowledgments:** This project was funded by the Hong Kong Jockey Club Charities Trust. We would like to thank the respondents who completed the telephone surveys and the Public Opinion Programme (HKU) for conducting the interviews.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
