AI-GF-GNW on Prolonged Grief Reactions

• AI-Assisted Grief-Focused Guided Narrative Writing (Behavioral): Participants will independently complete the intervention writing tasks via the H5 platform. Participants were required to complete a 6-day, 3-session narrative writing task. Each session requires more than 20 minutes of uninterrupted writing. Session 1 requires describing the specific details and feelings of the bereavement event; Session 2 requires describing the negative impact of the event and one's own negative feelings; Session 3 requires a description of the positive impact of the event and one's own positive feelings, with a one-day interval between each session, synchronized with the NF-GF-GNW group. When participants complete and submit their writing, they will immediately receive a response generated by the AI large language model. Participants are not allowed to engage in any additional interaction with the AI large language model other than submitting writing content and receiving feedback.
• No-Feedback Guided Narrative Writing (Behavioral): All processes are the same as the AI-GF-GNW group, except that when participants complete their writing and submit, the platform will only display a "submission successful" prompt and will not provide any feedback on the writing content.
• Free Writing (Behavioral): Participants in the FWG will not receive structured guidance, and are only required to write freely about their loss experiences. The writing sessions will follow the same schedule and duration as the other groups.

Primary outcomes

• Prolonged Grief Disorder-13-Revision (PG-13-R) [Baseline (0 Day), post-treatment assessment (5 Day), follow-up assessment (35 Day)]: PG-13-R is a standardized diagnostic tool designed to assess the severity of prolonged grief disorder symptoms over the past month. The instrument consists of 10 questions scored on a 5-point Likert scale, alongside 2 true/false questions and 1 open-ended question assessing functional impairment and duration.Who gets 30 points or higher will be considered as clinical prolonged grief reactions.
• Patient Health Questionnaire (PHQ-9) [Baseline (0 Day), post-treatment assessment (5 Day), follow-up assessment (35 Day)]: PHQ-9 is a brief, validated screening tool used to measure the severity of depression symptoms in adolescents over the past two weeks. 9 questions are scored on a Likert scale of 0-3 with 0 being not at all and 3 being nearly every day.

Secondary outcomes

• Generalized Anxiety Disorder (GAD-7) [Baseline (0 Day), post-treatment assessment (5 Day), follow-up assessment (35 Day)]: GAD-7 is an easy-to-perform initial screening tool for generalized anxiety disorder. Questions are scored on a Likert scale of 0-3 with 0 being not at all and 3 being nearly every day.
• WHO Disability Assessment Schedule-short version(WHODAS 2.0) [Baseline (0 Day), post-treatment assessment (5 Day), follow-up assessment (35 Day)]: WHODAS 2.0 is a comprehensive instrument developed by the World Health Organization to measure health status and functional disability across six core domains over the past 30 days. 12 questions are scored on a Likert scale of 1-5 with 1 being no difficulty and 5 being extreme difficulty.

Sex: All, ages: 10 Years to 19 Years, accepts healthy volunteers

Inclusion Criteria:

* Junior and senior high school students currently studying in Chinese Mainland, aged 10-19;
* Between 6 and 60 months prior to the experimental period, experienced the death of a significant family member or close friend or close friend;
* The total symptom score of PG-13-R is between 20-29 points;
* Ability to write and understand written guidelines, to use the mobile phone to interact with AI;
* Consent to participate in the study.

Exclusion Criteria:

* Diagnosed or previously diagnosed with mental illness
* The bereavement time does not meet the time window
* PG-13-R score is not within the range
* At present, there is suicidal ideation or recent severe self harm behavior (Reynolds' Suicidal Ideation Questionnaire, SIQ-JR-4>0), and a crisis intervention hotline is provided when necessary.
* Has received other grief counseling or is currently taking psychiatric medication within the past month