Is a mobile phone app delivering cognitive behavioural therapy effective at helping people quit smoking?

INTERVENTION: Randomisation: Participants are randomly assigned into the treatment and control arm at a 50:50 ratio. Group 1 (Intervention): Participants in the intervention arm receive access to a behavioral intervention (cognitive behavioral therapy; CBT) delivered through a mobile application. This consists of several sessions per week completed by the participant on their phone at their convenience, and without involvement of a healthcare professional. Group 2 (control): Those in the control arm receive a session of “very brief adviceâ€? delivered by a trained professional immediately after randomisation. More information is available at http://www.ncsct.co.uk/publication_very‐brief‐advice.php. Duration of treatment: 4‐weeks Duration of follow‐up: 1 year We confirm that there is no wash‐out period between the two trial conditions as this is not a crossover trial. CONDITION: Tobacco use ; Mental and Behavioural Disorders ; Tobacco use PRIMARY OUTCOME: Abstinence at 4 weeks post agreed quit date confirmed as self‐reported “no puff of smokeâ€? (using a questionnaire) in the past 2 weeks. SECONDARY OUTCOME: ; All outcomes are assessed using questionnaires completed by the participant.; 1. Successful quit attempt as defined in the primary outcome at 26 and 52 weeks.; 2. 7‐day point prevalence abstinence at week 4, 26, and 52.; 3. Number of quit attempts at week 4, 26, and 52.; 4. Client Satisfaction with the intervention at week 4 (treatment only).; 5. Participant changes in confidence levels, knowledge, attitudes and perceptions related to smoking cessation at week 4.; 6. Participant changes in self‐efficacy at week 4, 26, and 52.; 7. Participant changes in self‐reported health and wellbeing at week 4, 26, and 52.; INCLUSION CRITERIA: 1. Aged 18 or older 2. Has been smoking at least five cigarettes a day for at least one year 3. Desires to quit in the next 30 days 4. Can attend appointments at one of several locations around London 5. Using Apple iPhone (5th generation or higher) or Android phone (version 18 or higher) 6. Working proficiency in English language