The research aims to investigate the effectiveness of playback theatre program on improving mental health for adolescents and youth.

This study adopts a multicentre randomized control trial two arms research design. A randomised controlled trial will compare a typical 7-session therapeutic song-writing program with a waitlist-control group to determine whether the 7-session playback theatre program can produce better outcomes for young people with depressive symptoms, including improvement in depressive symptoms, self-stigma, self-esteem, sense of hope and social support at post-intervention. The 7-session playback theatre program will be delivered by trained and experienced social workers and helping professionals who are familiar with music therapy. A research staff, who does not involve in the group allocation and delivery of group intervention, conduct the intervention outcomes assessment of the participants before and after the intervention. Standardized assessment tools are used to assess the intervention outcomes. The ethical considerations of this study were reviewed and approved by the Human and Artefacts Ethics Sub-Committee of the City University of Hong Kong in 2026.

Mental health problems are very common among adolescents and youth in Hong Kong and worldwide. In Hong Kong, 24.4% of children and adolescents had at least one mental health problem in 2022. Mental health problems have negative effects on adolescents' health and academic performance, including suicide, alcohol and drug abuse, smoking, binge eating, diabetes, asthma and poor school performance. In particular, the risk of suicide among secondary school students is alarming in Hong Kong. 8.4%, 3.8% and 2.3% of secondary school students had a suicidal idea, plan or attempt in 2022, and the number of students who took their own lives in 2023 has increased by about 30% compared to the average of the past three years.

Psychosocial interventions have been shown to be effective in improving the mental health of adolescents and youth. Among the different types of psychosocial interventions, playback theatre program has been shown to be effective in improving depression, anxiety and self-esteem. In a typical playback theatre, participants play the roles of a teller, the conductor, the actors and the audience. After a short introduction, the conductor asks the members of the audience to tell a moment or feeling from their lives. After the teller sharing the story, the actors immediately improvise a piece of theatre, in which they reflect back the story with empathy. Playback improvisation can have a powerful effect on the storyteller, the actors and the audience.

The playback theatre program is a part of the "Everyone is a Hope Builder" organized by The Salvation Army of Hong Kong. As far as we know, no research study has been conducted on the effectiveness of a therapeutic song-writing program on improving the mental health of adolescents and youth in Hong Kong. Given this research gap, this research aims to explore the effectiveness of the therapeutic song-writing on young people with depressive symptoms.

Research Method This research study adopts mixed methods research design, involving both quantitative and qualitative study. The quantitative study aims to investigate the effectiveness of the playback theatre program for adolescent and youth people with depressive symptoms. The qualitative study aims to examine the benefits, advantages and limitations of the playback theatre program from the users' perspective. The ethical considerations of this study were reviewed and approved by the Human and Artefacts Ethics Sub-Committee of the City University of Hong Kong in 2026.

Quantitative Research Method Objective. This quantitative study aims to investigate the effectiveness of the playback theatre program for adolescents and youth with mental health issues.

Research Design. This study is a multicentre randomised waiting list control study. Eligible participants will be recruited from local secondary schools and Salvation Army social service centres in different districts, through open recruitment via promotional activities and referrals from these centres. A total of 120 participants will be recruited over a study period of approximately 15 months. Using block randomisation, 120 eligible participants will be randomly allocated in a 1:1 ratio to an intervention group or a waitlist control group. 60 participants in the intervention group will receive a playback theatre program. 60 participants on the waiting list will not receive an intervention in the initial phase, but will receive the same playback theatre program at a later stage. 5 intervention groups and 5 waitlist control groups will be conducted, with each intervention group consisting of 12 participants. A research assistant, blinded to randomised allocation, will conduct pre- and post-intervention outcome assessment using standardised assessment tools. See Figure 1 for the flow of participants through each stage of the study.

Hypotheses: After completing the playback theatre program, participants will show significantly greater improvement in depressive symptoms, anxiety symptoms, self-stigma, self-esteem and sense of hope at post-intervention.

Subject inclusion and exclusion criteria.

Subject exclusion Criteria:

1. aged between 13 to 24 years;
2. having mild to moderate depression and/or anxiety as assessed using a standardized assessment tool, i.e. Chinese Depression Anxiety Stress Scale-Youth (DASS-Y) with a DASS-Y Depression score between 5 and 12;
3. service users of The Salvation Army social service unit; and
4. giving informed consent to this research work. For those aged below 18, parental consent will be obtained.

Subject exclusion Criteria:

Those with severe depression (i.e. a DASS-Y Depression score ≥ 13) and severe anxiety (i.e. a DASS-Y Anxiety score ≥ 8) are excluded from this study.

Sample Size Estimation. The sample size of this study is estimated by using power analysis G*Power 3.1. Studies on interventions suggest a small to medium effect size on reducing depressive symptoms (Cohen's d ranges from 0.4 to 0.7). This study aims to demonstrate a medium effect size (i.e., Cohen's d = 0.5) with a statistical power of 0.80 for all intervention outcomes. A minimum sample size of 82 participants is required. Since a dropout rate of 30% is considered, a total of 120 participants are recruited.

Intervention group. The playback theatre program consists 7 session. One session will be conducted per week, with each session lasting for about 90 minutes. A social worker and a helping professional who is familiar with music therapy will be recruited to run the playback theatre program at a collaborative social service centre and school. A standardized program manual is designed by the research team. The social worker and a counsellor who run the playback theatre program will receive training and supervision on conducting the playback theatre program by the research team.

Outcome assessment tools. The Chinese Depression Anxiety Stress Scale (DASS; Wang et al., 2016); The Chinese Internalised Stigma of Mental Illness (ISMI; Young et al., 2017b); The Chinese Rosenberg Self-Esteem Scale (RSES; Leung & Wong, 2008); The Chinese Hope Scale (HOPE; Ho et al., 2012); The Chinese Multidimensional Scale of Perceived Social Support (MSPSS; Yang et al., 2024)

Data analysis. An analysis will be performed in accordance with the intent-to-treat principle using multiple imputation method analysis for any missing data. For all analyses, two-tailed p values of < 0.05 is considered statistically significant. Data analyses will be performed using SPSS 29.0 (IBM Corporation, 2022). Within group intervention effects are investigated using pair-sample t-test. Between group intervention effects are investigated using 2 (group) x 2 (time) repeated measures of one-way analysis of variance (ANOVA). Within and between group effect sizes are computed using Cohen's d, with values of 0.2, 0.5, and 0.8 considered as small, medium, and large respectively (Cohen, 1988).

Fidelity of intervention. Standardized program manuals of playback Theatre program will be developed by a project team of The Salvation Army. The program manuals will be reviewed by experts in playback theatre program. The social workers delivering the playback theatre program in this project will receive the program manuals, training and supervision from the project team to ensure that the intervention groups follow the playback theatre program manual.

Qualitative Research Method Objective. This qualitative study aims to explore the benefits, advantages and limitations of the playback theatre program from the users' perspective.

Research Design. The qualitative study uses an interpretative interview method with purposive sampling. 5 focus groups will be conducted, with each focus group consisting of 2-4 participants selected from each intervention group.

Data collection. Each focus groups will be facilitated by a research staff with an interview protocol developed for this study. Participants will be asked questions such as the following: "In what ways, if any, did the intervention group help you to improve your mental health such as depression and anxiety"; "In what ways, if any, did the intervention group help you to improve self-esteem and build up a sense of hope?"; "What are the advantages and limitations, if any, of the intervention group?"; "and "Any suggestions, if any, for improving the intervention group?". The results of the qualitative analysis will provide insights for further development and modifications of the playback theatre program.

Data analysis. The content of focus groups will be audio-recorded and transcribed into verbatim by the research team. All transcripts of the focus groups will be coded. These codes will then be reviewed and grouped into broader categories and subcategories, resulting in themes and subthemes.

Reflective thematic analysis will be used to identify, analyse and report themes so that themes can be developed both inductively (i.e. data-driven) and deductively (i.e. theory-driven) (Campbell et al., 2021). The research team will systematically read and re-read the transcripts, following the six stages of analysis, including: (1) becoming familiar with the data, (2) generating codes, (3) constructing themes, (4) reviewing potential themes, (5) defining and naming themes, and (6) producing the report (Braun & Clarke, 2022). Two research staff compare, review and refine the codes, categories and themes until they reach agreement.

Inclusion Criteria:

1. aged between 13 to 24 years;
2. having mild to moderate depression and/or anxiety as assessed using a standardized assessment tool, i.e. Chinese Depression Anxiety Stress Scale-Youth (DASS-Y) with a DASS-Y Depression score between 5 and 12;
3. service users of The Salvation Army social service unit; and
4. giving informed consent to this research work. For those aged below 18, parental consent will be obtained.

Exclusion Criteria:

Those with severe depression (i.e. a DASS-Y Depression score ≥ 13) and/or severe anxiety (i.e. a DASS-Y Anxiety score ≥ 8) are excluded from this study.

A research staff, who is blinded to the group allocation and does not involve in the delivery of group interventions, conduct the intervention outcomes assessment of the participants before and after the intervention.