Background <p>Magnetic resonance imaging (MRI) can personalise the site of transcranial magnetic stimulation (TMS) delivered as a course of 20 sessions for treatment-resistant depression (TRD). Facilitators and barriers to a randomised controlled trial (RCT) of MRI personalised TMS is understudied.</p> Aim <p>Qualitative analysis to explore facilitators and barriers behind RCT participants’ experience of personalised MRI-targeted TMS in people with TRD.</p> Methods <p>Nineteen participants from the BRIGhTMIND RCT of two forms of MRI personalised TMS, completed semi-structured interviews exploring the reasons behind the uptake and experience of TMS. The sample included fifteen participants who completed the treatment course and four who declined to proceed before randomisation. Interviews were analysed using thematic analysis, co-produced between researchers and patients and public involvement contributors.</p> Results <p>Facilitators were “hope” regarding the treatment itself, the influence of research staff, interest in a new treatment, and altruism. Barriers were concerns about their ability to commit to the trial and the nature of the TMS itself. Throughout the themes, clinicians and researchers made a difference by explaining and setting realistic expectations of the treatment and building rapport through daily patient contact.</p> Conclusion <p>The study highlights the importance of understanding patients’ concepts and experiences of TMS. The provision of optimal information to patients twinned with offering TMS outside office hours and the most efficacious, acceptable regimes of TMS delivery may maximise participation (Trial registration number ISRCTN19674644, registered on 01/10/2018).</p> Trial Registration <p>Trial registration: ISRCTN19674644||<a href="http://www.isrctn.org/">http://www.isrctn.org/</a>) registered on 01/10/2018.</p> <p>Trial Identifying numbers: CPMS 39297, IRAS 245025.</p>