Like many good ideas, cognitive behavioural therapy (CBT) has gone through multiple waves of development. One view is that third-wave CBT is now rolling in, as theory and practice have moved beyond behavioural therapy, through to the incorporation of ideas from cognitive psychology, to more modern adaptations.

Third-wave CBT encompasses many of the innovations and extensions now commonly considered under the umbrella of CBT. In particular, it includes mindfulness-based approaches, dialectical behaviour therapy, and acceptance and commitment therapy. The key defining feature is that these therapies are less based on a classical biomedical model and more concerned with addressing problems in functional and contextual terms.

There is debate about what counts as third-wave CBT. But, whatever you want to call these modern ‘contextual’ incarnations of CBT, there is some evidence to support them (e.g. McDonald 2016). Clinical effectiveness has been demonstrated for particular forms of therapy in a variety of contexts (and so, they are sometimes used in practice), but are they cost-effective, and do they represent good value for money? A recent study by Feliu-Soler and colleagues (2018) reviews the evidence on the cost-effectiveness of third-wave CBT.

Methods

The authors conducted a systematic review of published economic evaluations that were conducted alongside randomised controlled trials (RCTs). That means that non-randomised studies were excluded, as were economic evaluations based on modelling.

The included therapies were:

• Mindfulness-Based Cognitive Therapy (MBCT)
• Acceptance and Commitment Therapy (ACT)
• Extended Behavioural Activation (eBA)
• Dialectical Behaviour Therapy (DBT)
• Mindfulness-Based Stress Reduction (MBSR)
• Functional Analytic Psychotherapy (FAP)
• Cognitive Behavioural Analysis System of Psychotherapy (CBASP)
• Compassion-Focused Therapy (CFT)
• Mindfulness-Based Relapse Prevention (MBRP)
• Mindfulness-Based Eating Awareness Training (MB-EAT)
• Metacognitive Therapy (MCT)
• Integrative Behavioural Couple Therapy (IBCT)

The quality of the studies and the risk of bias was assessed using Cochrane-recommended tools.

Results

The search turned up 765 unique citations. After exclusions, eleven papers describing RCTs were included.

Sample sizes were generally small, ranging from 19 to 221, and durations of the studies were mostly short, ranging from 3 to 26 months. Of the 12 different types of therapy included, five were represented in the review: MBCT, ACT, eBA, DBT, and MBSR.

For all of the five therapies, the evidence was at best partially favourable. I would summarise the data as shown in the table below, where:

• ✓ = “probably cost-effective”,
• ☓ = “probably not cost-effective”, and
• ? means that the evidence is ambiguous.

	MBCT	ACT	eBA	DBT	MBSR
Depression relapse / major depression	?		✓
Somatoform disorders	☓
Multiple sclerosis	✓
Pain / fibromyalgia		✓
Personality disorders				?
Breast cancer					?

With five papers, MBCT was the only therapy with more than two studies. And the evidence isn’t consistent. Even within the context of depression, two of the larger studies disagreed about whether MBCT was likely to be a cost-effective strategy.

The evidence suggests that ACT is more effective and cost-saving for chronic pain patients, and that eBA is cost-effective for major depression, but these findings are based on just two studies each.

None of the studies evaluated the consequences of interventions beyond three years, and the assessments of quality and risk of bias gave some reason for concern.

Conclusions

Compared to second-wave CBT, we’re still in the early days of evidence generation for third-wave CBT, especially with respect to the economic evidence.

A key conclusion is that more economic evaluations of third-wave therapies are needed. These should be directed towards those therapies and indications for which clinical effectiveness has been established. The authors suggest ACT, CBASP, and DBT as good candidates.

Strengths and limitations

The review appears to be comprehensive with respect to different third-wave therapies. The assessments of the risk of bias and methodological quality of the included studies is an important strength of this review.

For a majority of the therapies considered in the review (seven of twelve), there was no evidence available. This is the main limitation of the review, because it is not able to inform us on the cost-effectiveness of even most third-wave therapies, let alone all of them. So, we aren’t able to conclude anything about third-wave therapies in general.

The other major limitation of the review is that no two studies included are easily comparable, meaning that the review can provide little more than the sum of its parts. The evidence summarised does not allow us to say anything conclusive about any of the individual therapies.

A limitation that I would highlight (not discussed by the authors) is that restricting the review to trial-based studies could overlook important information. Increasingly, decision-making relies on model-based economic evaluations, which combine information from multiple sources and settings (Sculpher et al 2006). Trial-based economic evaluation is not a prerequisite for supporting the implementation of a new technology, so it does not follow that evidence reviews should restrict themselves in this way.

Implications for practice

The use of MBCT, ACT, and eBA might be cost-effective for certain groups of patients, but with no more than two supportive studies in any given context, we can’t say anything with confidence. Based on this review, there isn’t an adequate evidence base to support the use of third-wave therapies in any context, implying that they shouldn’t be used in practice.

However, as the authors of this review point out, the generation of new evidence is well underway. This review only searched for papers published before May 2016, which is a long time for a growing evidence base. A review conducted in the near future could find very different evidence and provide more compelling implications for practice.

Conflicts of interest

None

Links

Primary paper

Feliu-Soler A, Cebolla A, McCracken LM, D’Amico F, Knapp M, López-Montoyo A, García-Campayo J, Soler J, Baños RM, Pérez-Aranda A, Andrés-Rodriguez L, Rubio-Valera M, Luciano JV. (2018) Economic Impact of Third-Wave Cognitive Behavioral Therapies: A Systematic Review and Quality Assessment of Economic Evaluations in Randomized Controlled Trials. Behavior Therapy, 49(1): 124-147

Other references

McDonald S (2016) Mindfulness-based cognitive therapy can prevent recurrent depression. The Mental Elf.

Sculpher MJ, Claxton K, Drummond M, McCabe C. (2006) Whither trial-based economic evaluation for health care decision making? Health Econ 15(7): 677-87

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