Treatment-resistant depression (TRD) is common, severe and long-lasting, contributing substantially to the overall burden of depression. Treatments for depression/TRD are still prescribed via trial-and-error, despite accumulating evidence that certain factors can predict response to different interventions. Extant evidence of TRD outcome prediction is limited by small samples, short-term outcomes and artificial treatment settings. We have conducted a large, long-term randomized controlled trial (RCT) of first-line TRD treatments. Unlike most RCTs, the LQD study was pragmatic in nature and therefore better reflects real-world outcomes. We also followed participants up for 12months, permitting a more valid prospective assessment of treatment outcomes. Focusing on currently recommended TRD therapies also contrasts with most existing research, assessing lesser-used therapies. Finally, we will employ a clinical outcome that is meaningful to patients.
Our overarching aim is to develop a model comprising factors that are feasible to assess in routine practice and predict outcomes to the recommended augmenters for TRD. Specific objectives comprise:
1) Define a priority outcome for patients, through literature review and consultation with those affected by depression/TRD.
2) Examine pre-treatment factors to develop a model predicting long-term outcomes from the LQD study.
3) Validation of the model in other studies of emerging therapies for TRD e.g., psilocybin, ketamine.
Planned research methods and training:
Additional to trans-project training (e.g., coding), we will provide high-quality training in:
1) Systematic review (objective1),
2) Qualitative research (objective1),
3) Involving patients in research (objective1),
3) Prediction modelling (objective 2&3).
Objectives / project plan:
Year1: Systematic review & PPIE consultation/consensus resulting in a definitive outcome variable for objectives 2/3.
Year2: Hypothesis generation and prediction model development. Objective 2 data cleaning and analyses.
Year3: Objective 3 access to dataset(s), data cleaning and analysis, to observe potential application of the model to novel TRD therapies.
Year4: Interpretation and thesis write-up.