Study strengths and limitations
Participants were all white British; this limits the study's transferability to people of different backgrounds. Furthermore, the lack of a longer‐term follow‐up means that we could not show whether intervention mechanisms were maintained long‐term. The sampling method may have contributed towards bias. Participants consisted of those from the ESCAPE trial who had attended three or more sessions, completed at least one follow‐up and had self‐selected to attend interviews. This population may have had more positive experiences of the intervention compared to those not sampled, which may not represent the experiences of all intervention arm participants. In addition, as participants were also part of a larger study that was not designed to investigate mechanisms of smoking cessation, it is unknown if these findings are transferable to the general IAPT population. However, studies of participants who were not selected to take part in an RCT are predictive of some of the findings in this study. For example, in another study of IAPT users, participants prospectively predicted that knowing about the mental health benefits of smoking cessation could help them to quit smoking.When interpreting qualitative results, it is important to acknowledge the researcher's backgroundThis study has considerable strengths. According to Malterud's et al.