Personalising psychotherapies for depression using a novel mixed methods approach: an example from Morita therapy.

<bold>Background: </bold>Current quantitative methods for personalising psychotherapies for depression are unlikely to be able to inform clinical decision-making for hundreds of years. Novel alternative methods to generate hypotheses for prospective testing are therefore required, and we showcase mixed methods as one such approach. By exploring patients' perspectives in depth, and integrating qualitative and quantitative data at the level of the individual, we may identify new potential psychosocial predictors of psychotherapy outcomes, potentially informing the personalisation of depression treatment in a shorter timeframe. Using Morita therapy (a Japanese psychotherapy) as an exemplar, we thus explored how Morita therapy recipients' views on treatment acceptability explain their adherence and response to treatment.<bold>Methods: </bold>The Morita trial incorporated a pilot randomised controlled trial of Morita therapy versus treatment as usual for depression, and post-treatment qualitative interviews. We recruited trial participants from general practice record searches in Devon, UK, and purposively sampled data from 16 participants for our mixed methods analysis. We developed typologies of participants' views from our qualitative themes, and integrated these with quantitative data on number of sessions attended and whether participants responded to treatment in a joint typologies and statistics display. We enriched our analysis using participant vignettes to demonstrate each typology.<bold>Results: </bold>We demonstrated that (1) participants who could identify with the principles of Morita therapy typically responded to treatment, regardless of how many sessions they attended, whilst those whose orientation towards treatment was incompatible with Morita therapy did not respond to treatment, again regardless of treatment adherence and (2) participants whose personal circumstances impeded their opportunity to engage in Morita therapy attended the fewest sessions, though still benefitted from treatment if the principles resonated with them.<bold>Conclusions: </bold>We identified new potential relationships between "orientation" and outcomes, and "opportunity" and adherence, which could not have been identified using existing non-integrative methods. This mixed methods approach warrants replication in future trials and with other psychotherapies to generate hypotheses, based on typologies (or profiles) of patients for whom a treatment is more or less likely to be suitable, to be tested in prospective trials.<bold>Trial Registration: </bold>Current Controlled Trials, ISRCTN17544090. Registered on 23 July 2015. [ABSTRACT FROM AUTHOR]