IntEgrating Smoking Cessation treatment As part of usual Psychological care for dEpression and anxiety (ESCAPE): protocol for a randomised and controlled, multicentre, acceptability, feasibility and implementation trial.

Background: People with depression/anxiety are twice as likely to smoke and are less responsive to standard tobacco treatments, leading to a reduced life expectancy of up to  13.6 years compared to people without depression/anxiety. However, this group of smokers is motivated to quit, and as a result of quitting smoking, their depression/anxiety is likely to improve. In England, people with depression/anxiety are referred to a primary care-based psychological therapies service known as 'Improving Access to Psychological Therapies' (IAPT), which could offer smoking cessation treatment as part of usual care but currently does not. In this study, we aim (1) to establish the feasibility and acceptability of delivering a smoking cessation treatment alongside IAPT usual care and (2) to establish the feasibility of a multi-centre randomised trial to compare the combined smoking cessation and IAPT treatment to usual IAPT treatment alone.

Methods: A randomised and controlled, multi-centre trial to test the acceptability, feasibility and implementation of smoking cessation treatment as offered alongside usual IAPT care, compared to usual care alone, with nested qualitative methods. We will include adult daily smokers with depression/anxiety, who would like help to quit smoking and are about to start IAPT treatment. Follow-up will be conducted at 3-months after baseline. The main outcome will be retention in the smoking cessation treatment. Secondary outcomes are smoking-related (biochemically-verified 7-day point prevalence smoking cessation, number of cigarettes smoked per day, Heaviness of Smoking Index), mental health-related (PHQ-9), service-related (number of 'Did Not Attends', number of planned and completed IAPT sessions), acceptability and feasibility (participant and clinician acceptability and satisfaction of intervention as assessed by questionnaires and qualitative interviews, interviews will also explore acceptability and feasibility of data collection procedures and impact of smoking cessation treatment on usual care and mental health recovery) and implementation-related (intervention delivery checklist, qualitative analysis of intervention delivery).

Discussion: If the intervention is shown to be acceptable, feasible and suitably implemented, we can conduct a randomised controlled trial. In a future trial, we would examine whether adding smoking cessation treatment increases smoking abstinence and improves depression and anxiety more than usual care, which would lead to long-term health improvement.

Trial registration: ISRCTN99531779.