An expert consensus on the most effective components of cognitive behavioural therapy for adults with depression: A modified Delphi study

Cognitive behavioural therapy (CBT) is an effective treatment for depression but many people still cannot access therapy. Delivering CBT via the internet has the potential to provide a widely accessible and cost-effective solution to improving access to psychological treatment. Whilst some studies have found that computerised CBT is acceptable to both patients and therapists, trial outcomes have been mixed and there is some evidence that important therapeutic elements of face-to-face CBT are lost when therapy is delivered purely online. Therefore, in order to optimise the design of new approaches to delivering CBT, improve the efficiency of treatment and prevention of relapse, it is important to understand the key components or ‘active ingredients’ of therapy.

CBT is characterised by a core set of components, which are given different emphasis depending on the preferred approach of the therapist and the needs of the client. It is likely that some of these components are more important to the success of therapy than others but, at present, we have little evidence to enable us to identify the key components of CBT.

Our aim in this study (recently published in Cognitive Behaviour Therapy) was to establish an expert consensus on the effective components of CBT for depressed adults. We used an approach called the Delphi method that uses a process of repeated surveys to converge individual opinion into a group consensus. Study participants anonymously rate items in a survey, are then provided with feedback on the group response and are asked to re-rate their initial responses considering this information.

An international panel of 120 CBT experts was invited to participate in a modified Delphi study that was conducted online. Thirty-two experts participated in round 1, with twenty-one experts also providing data in round 2.

In round 1, experts rated the effectiveness of a ‘long list’ of 35 CBT components. The components were grouped into ‘content components’ which were those expected to facilitate behavioural change, such as thought restructuring and activity scheduling, and ‘process components’ which are procedures for the delivery of therapy, such as who provides therapy, the number and frequency of sessions, support between sessions and the mode of delivery.

Components carried forward to round 2 were identified using pre-specified rules. In round 2, experts re-rated items and final consensus items were identified.

Consensus was achieved in relation to nine “content” components (ensuring understanding; developing and maintaining a good therapeutic alliance; explaining the rationale for CBT; eliciting feedback; identifying and challenging avoidant behaviour; activity monitoring; undertaking an initial assessment; relapse prevention methods; homework assignments) and three “process” components (ensuring therapist competence; scheduling sessions flexibly; scheduling sessions for 45-60 mins). Five of the twelve components identified were generic therapeutic competences rather than specific CBT items. There was less agreement about the effectiveness of cognitive components of CBT.

So what are the implications of this work?

Understanding the expert view on the key components of CBT is an important first step in the development of novel approaches to delivering CBT in a way that could increase access to treatment for depressed patients. Future studies using different methodological approaches will enable us to build on these findings and advance our knowledge about the key components of CBT. Research also needs to take advantage of opportunities to embed mechanistic studies within large-scale trials of CBT. Triangulating findings from studies using different methodological approaches will help us understand more about the ‘active ingredients’ of CBT. This may lead to improvements in access to depression treatment for the large number of patients who may benefit.

Read the full article: Taylor, A., Tallon, D., Kessler, D., Peters, T. J., Shafran, R., Williams, C., & Wiles, N. (in press). An expert consensus on the most effective components of cognitive behavioural therapy for adults with depression: A modified Delphi study.  Cognitive Behaviour Therapy. doi: 10.1080/16506073.2019.1641146

Pictured: Dr. Nicola Wiles

Photo by: WOCintech Chat (

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