Development of a Digital Acceptance and Commitment Therapy Intervention for Suicide Prevention in Adults Through Co-design

• Digital ACT Intervention (Behavioral): A co-designed digital Acceptance and Commitment Therapy (ACT) intervention for suicide prevention

Primary outcomes

• Intervention completion rate [End of the intervention (approximately 2 weeks)]: The intervention completion rate will be assessed as the percentage of participants who complete the digital intervention, based on intervention usage records.
• Retention rate [End of the 1-month follow-up]: The participant retention rate will be assessed as the percentage of participants who complete the post-intervention assessment and the follow-up assessment.
• Acceptability outcome [End of the intervention (approximately 2 weeks)]: Acceptability of the intervention will be assessed using participant-reported ratings and feedback regarding satisfaction and overall experience with the intervention.
• Usability outcome [End of the intervention (approximately 2 weeks)]: Usability will be assessed using the System Usability Scale (SUS), a 10-item self-report questionnaire. Total scores range from 0 to 100, with higher scores indicating better usability of the intervention.

Secondary outcomes

• Suicide ideation [Baseline, end of the 2-week intervention, and 1-month follow-up]: Suicidal ideation will be assessed using the Beck Scale for Suicide Ideation (BSSI). Each item is rated on a 3-point scale ranging from 0 to 2, with higher scores indicating greater suicidal ideation.
• Psychological flexibility and inflexibility [Baseline, end of the 2-week intervention, and 1-month follow-up]: Psychological flexibility and inflexibility will be assessed using the Multidimensional Psychological Flexibility Inventory-24 (MPFI-24). Each item is rated on a 6-point scale ranging from 1 to 6. Higher scores on the flexibility and inflexibility subscales indicate greater psychological flexibility and psychological inflexibility, respectively.
• Psychological Distress [Baseline, end of the 2-week intervention, and 1-month follow-up]: Psychological distress will be assessed using the Depression Anxiety Stress Scales (DASS). Each item is rated on a 4-point scale ranging from 0 to 3, with higher scores indicating greater psychological distress.
• Mental well-being [Baseline, end of the 2-week intervention, and 1-month follow-up]: Mental well-being will be assessed using the Mental Health Continuum-Short Form (MHC-SF). Each item is rated on a 6-point scale ranging from 0 to 5, with higher scores indicating greater mental well-being.

Other outcomes

• Qualitative Feedback and Design Recommendations [Through study completion, an average of 6 months]: Qualitative feedback related to user needs, preferences, barriers, facilitators, cultural considerations, and recommendations for intervention refinement will be identified from co-design activities and feedback sessions.
• Cultural Relevance [Through study completion, an average of 6 months]: Cultural relevance of the intervention will be assessed through participant feedback regarding the appropriateness, relevance, and cultural fit of the intervention content and delivery.

Sex: All, ages: 18 Years to any

* Inclusion Criteria Lived experience participants

  1. Aged 18 years or older;
  2. Have experienced suicidal thoughts and/or behaviors;
  3. Able to read and communicate in Chinese; Professionals

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  1. Aged 18 years or older;
  2. Professionals with experience relevant to suicide prevention, Acceptance and Commitment Therapy (ACT), digital mental health, or related fields;
* Exclusion Criteria

  1. Unable to provide informed consent or participate in study activities;
  2. Currently experiencing acute suicide risk requiring immediate intervention;
  3. Severe cognitive impairment or active psychotic symptoms that would prevent participation.

• Tao Zhang, Principal investigator, The Hong Kong Polytechnic University