The goal of this research is to better understand the active ingredients of online cognitive behavioural therapy so that we can build stronger, better and more widely available psychological treatments. Cognitive-behavioural therapy is a treatment approach that seeks to reduce depression by helping individuals to change their actions and thinking. When depressed, many people become more negative and self-critical and reduce their levels of rewarding activity. Cognitive-behavioural therapy teaches people to review their thinking and to put negative thoughts into perspective, as well as building up positive and self-nurturing activities. Numerous trials have shown this approach to be effective at reducing depression. However, there is still considerable scope to improve therapy because only one third of patients have sustained recovery that lasts over one year, and over 50% of successfully treated patients go on to have a further episode of depression (Hollon et al., 2002).

Furthermore, because of its high prevalence, traditional ways of delivering treatment such as face-to-face psychotherapy will never be able to adequately address the global challenge of depression. With approximately 10% of the population experiencing a major episode of depression in their lifetimes, there are simply not enough therapists available to reach all the people who will experience depression for face-to-face treatment. In addition, there is a pressing need to make effective therapies more available and more convenient for users (Kazdin & Blase, 2011) – such that the therapy can be accessed anywhere, anytime, and at the convenience of the user. Internet psychotherapy is a potential solution to increasing the reach, range, and availability of effective therapies, and has already been shown to be an effective treatment (Andrews et al., 2010).

To date, although clinical trials have shown that cognitive-behavioural therapy can reduce depression, we still don’t have a good idea of how exactly the therapy works. In particular, although cognitive-behavioural therapy has many different elements and ingredients, we don’t know which of these elements are the active ones causing improvement or indeed whether particular combinations of these elements may be more beneficial. This is a consequence of previous clinical trials, which have tended to compare one treatment with another treatment or with a placebo or no-treatment control condition, in “a horse race” to see which treatment does better. These comparisons look at the whole treatment package and are therefore unable to tell us which ingredients of therapy actively contribute to improvement.

An alternative approach gaining currency in behavioural science is the use of a fractional factorial experiment in which a balanced set of different combinations of the components within a treatment are compared to determine which treatment elements may be beneficial, inert, or even unhelpful. This approach enables us to to identify which elements of therapy to retain and refine in an efficient and systematic way, and, thereby, to build a stronger and more effective therapy. The application of this factorial approach to behavioural interventions has been pioneered by Professor Linda Collins at the Methodology Center, Penn State University, who is collaborating in this research (Collins et al., 2005, 2011). This approach is well-validated and recommended for treatment modelling within the MRC Complex Intervention guidelines.

Professor Watkins said that “Although cognitive-behavioural treatments work moderately well, we are still basically ignorant of what the active ingredients of therapy are. Understanding the active ingredients – and how they work together – is the key next step to improving psychological treatments for depression. It is particularly important to understand the interactions between treatment components because we know next to nothing about whether one ingredient of therapy –for example challenging negative thoughts works better or worse when combined with another ingredient of therapy such as relaxation. We know that there are interactions between drugs – with some combinations being more potent than others and it seems likely that a similar effect may occur in psychotherapy. This research provides the first attempt to address this important question in cognitive-behavioural therapy for depression. We hope that it will enable us to begin to assemble briefer, more cost-effective yet more powerful therapies on empirical and logical grounds, rather than by trial and error as previously.”

This innovative combination of a factorial design and internet delivery holds considerable promise to revolutionise our mechanistic understanding of psychological treatments for depression and to build enhanced interventions. This approach is novel and has yet to be applied within psychological treatments. To our knowledge, this study is the first to use this approach for improving psychotherapy for depression anywhere in the world.