Stratifying cognitive behavioural therapy for anxiety and depression: from discovery to impact

Essential background (up to 500 words including key references)

Describe background to the work including that carried out in the supervisor's own team and previous work. [This information will be used by the reviewers to understand the context of the proposed study].

Mood and anxiety disorders are incredibly disabling and increasingly common, particularly in young adults. The leading evidence-based treatment is Cognitive Behavioural Therapy (CBT), but as with medication, only around 50% of those treated recover. There is an urgent need to improve our understanding of what works for whom, enabling stratified treatment.

The NHS Talking Therapies service offers CBT and other psychological treatments to patients with anxiety or depressive disorders. One of their providers is ieso. ieso is the largest UK provider of online typed one-to-one CBT, delivering treatment to patients through both low- or high-intensity interventions. Our KCL team have been working with ieso scientists for several years building a robust collaboration with two completed projects exploring outcomes following psychological treatment1.

We now propose a new jointly developed collaboration which will push this work from discovery through to translation.

Existing studies including ours have shown treatment response is related to specific patient characteristics. Analyses of ieso, NHS Talking Therapies services more widely, and clinical trial data have identified clinical, demographic and environmental predictors of poor treatment response1-3. Notably, symptom severity, comorbidity, unemployment, disability and trauma are all associated with poorer responses to CBT.

Taken together, these predictors account for ~20% of the variance in continuously assessed outcomes3, but this is insufficient to accurately identify groups who will respond and who will not.

This project aims to go further by identifying how treatment response is related to therapy content. By adopting a more granular approach, we will identify which patients respond to which CBT protocols or specific therapeutic elements. This is possible because of the nature of ieso's typed therapy model, which records every interaction between patient and therapist.

We will explore predictors of response to different CBT protocols and therapeutic elements in patients treated for anxiety or depression within (1) ieso's standard care pathway and (2) a new smartphone digital therapy app developed and delivered by ieso. Finally, using these data we will test whether we can improve treatment response rates by stratifying CBT protocols/therapeutic elements based on what has been learned.

Aim of the investigation (up to 150 words) State primary research question and where appropriate the primary hypotheses being tested

To build a multivariable model to predict outcomes following CBT for depression or anxiety that explicitly examines (a) the CBT protocol and (b) therapeutic elements using: ieso's treatment-as-usual data; ieso's smartphone app treatment data.

To conduct a clinical trial testing whether specific patient groups do better when offered a "stratified" form of CBT.