"Real-time Smoking Cessation Instant Messaging Support Using a Large Language Model (LLM)-Based Chatbot Via Quit to Win 2025 (QTW2025)"

AWARD advice include Ask about smoking history, Warn about the high risk, Advise to quit, Refer smokers to smoking cessation services (with a referral card), and Do it again.

The contents of the leaflet include (1) highlights of the absolute risk of death due to smoking; (2) the whole list of diseases caused by active and second-hand smoking; (3) ten horrible pictorial warnings of health consequences of smoking and second-hand smoking in one page to maximize the impacts; (4) benefits of SC and (5) simple messages to encourage participants to quit smoking.

The contents consist of brief information and a highlight of existing smoking cessation services, contact methods, motivation information and strong supporting messages or slogans.

The contents include information about the benefits of quitting, smoking and diseases, methods to quit, how to handle withdrawal symptoms, declaration of quitting, etc.

Smokers will be introduced to various SC services in Hong Kong (using the referral card) and be motivated to use these services. Well-trained SC ambassadors will assist smoker to choose favourite/most convenient or preferred type of services. Research staff will assist participants in booking or re-booking the SC services at the 1- and 2-month follow-ups (after very brief questionnaire surveys). Participants' contact information will be forwarded to SC services providers within seven days, and providers are expected to contact the participants within 1-2 weeks. Research staff will also monitor SC services use of the participants at each follow-up (1-, 2-, 3- and 6- month) and assist participants to book or re-book the appointments if necessary at 1- and 2- month follow-up. We shall liaise with the existing service providers and seek their assistance in helping our smokers in helping our smokers in a timely manner.

Participants in the intervention group will receive 12 weeks of instant messaging support delivered by the LLM-based chatbot accessible via WhatsApp platform. The chatbot, powered by GPT-4o model (or more advanced model available) using prompt-engineering and agent-based techniques, will deliver brief theory-based, structured SC intervention alongside freeform, on-demand support. The structured intervention session deploys the 5As model (Ask, Advise, Assess, Assist, and Arrange follow-up) and 5Rs model (Relevance, Risks, Rewards, Roadblocks, Repetition), as used in our previous telephone-counselling trials and recommended by WHO for brief SC intervention.

WhatsApp messages on follow-up survey reminders.