Transdiagnostic psychological treatments for anxiety and depression

There has been recent interest in the development of transdiagnostic treatments for anxiety and depression (Craske, 2012). In this article, we discuss why this has come about, the potential advantages transdiagnostic treatment offers, what it involves and whether it actually delivers on its promise.

Why the interest in transdiagnostic treatment?

The high prevalence and cost of anxiety and depressive disorders have resulted in unprecedented efforts to support dissemination of evidence-based treatments for these conditions. Although there is extensive evidence for psychological treatments for each anxiety disorder and depression (i.e. disorder-specific cognitive behaviour therapy [DSCBT]), this model of treatment does have some limitations.

In the community, the most common presentations are a mix of anxiety and depressive symptoms rather than pure disorders. Anxiety and depressive disorders are also highly comorbid, both with each other and other anxiety disorders. Somewhat surprisingly in view of this, remarkably few studies address the question of how the treatment of mixed anxiety and depression, or comorbid anxiety and depressive disorders is best addressed. For example, should DSCBT be offered for just one disorder or to both sequentially, which disorder is treated first and what are the costs of this?

A further concern with DSCBT relates to training and dissemination. In research and specialist settings, there is no problem training clinicians in each of the treatment models and their delivery. This is, however, more challenging in real-world settings where clinicians have funding restrictions on the number of sessions they can provide, are often not from a psychology background and have limited access to training and supervision. It has been suggested that these factors have resulted in the poor dissemination of evidence-based treatment into clinical practice.

Transdiagnostic treatment may go some way to addressing these issues. From a service delivery perspective, focussing treatment on presentations which are often a mix of anxiety and depressive symptoms, or anxiety and depression with comorbidity rather than specific disorders, is likely to be beneficial. From a training perspective, clinicians only need to be trained in a single model of treatment which they can not become confident in delivering. In addition, there is often a drive for treatments to be delivered in a group format for pragmatic reasons (e.g. efficiency, cost-effectiveness). A transdiagnostic approach facilitates this because people with different disorders can all be started in a group, whereas in a disorder-specific approach, there is often delay in collecting together sufficient numbers with the same diagnosis presenting at a similar time.

What are transdiagnostic treatments?

Transdiagnostic treatments target the core, maladaptive temperamental, cognitive, emotional and behavioural processes and symptoms that underlie a variety of presentations. This means that the same treatment principles can be applied across disorders rather than being tailored to specific diagnoses.

Transdiagnostic treatments have been developed from two broad approaches. The first has been a pragmatic approach, by clinicians working in Community Mental Health Clinics which have bought together elements from various disorder-specific treatment protocols and effectively offered broad-spectrum transdiagnostic cognitive behaviour therapy (TCBT). This has been used in diagnostically mixed samples and usually in group formats. Treatment focuses on common elements, e.g., psychoeducation, self-monitoring, cognitive restructuring and exposure to feared stimuli. The final stages focus on cognitive therapy strategies for non-disorder-specific beliefs relating to perceptions of uncontrollability, unpredictability and threat.

The second approach has been theory driven and resulted in the Unified Protocol (UP) for the treatment of emotional disorders (Farchione et al., 2012). This proposes that a common underlying factor across anxiety and depression is the propensity towards increased emotional reactivity coupled with a heightened tendency to view these experiences as aversive. The UP distils the common principles from existing psychological treatments, i.e., restructuring maladaptive cognitive appraisals, changing maladaptive action tendencies associated with emotions, preventing emotion avoidance and utilising emotion exposure procedures. It also places explicit emphasis on the adaptive function of emotions and builds on the patient’s awareness of the contribution of cognitions, physical sensations and behaviours to unfolding emotional experiences and identifies and alters maladaptive reactions to these experiences. The treatment comprises modules targeting motivational enhancement, psychoeducation and understanding emotions, emotional awareness training, cognitive reappraisal, attenuation of emotional and behavioural avoidance, awareness and tolerance of physical sensations, interoceptive and situational exposure and relapse prevention.

Does transdiagnostic treatment deliver on its promise?

The short answer is that it is currently too early to say.

The most researched treatments have been TCBT for either multiple anxiety disorders or anxiety and depression and have utilised different formats of delivery, i.e., individual, group, computerised and on-line. It is important to note that many of these studies have been of small sample size, of open design or randomised controlled trials (RCTs) where the comparator has been a wait-list control or treatment as usual. There have been very few RCTs which have compared TCBT with DSCBT (the recognised gold standard psychological treatment). In addition, the published studies were often led by developers of the treatment which means that investigator allegiance may have unintentionally overestimated their efficacy. There have been two meta-analyses of face-to-face TCBT for anxiety disorders (Norton and Philipp, 2008; Reinholt and Krogh, 2014) and one which has included all 47 studies for depression and/or anxiety disorders (i.e. including Internet TCBT; Newby et al., 2015). These have concluded that TCBT was as efficacious as DSCBT, but although promising, future research is needed, particularly in comparing TCBT to DSCBT, in determining who might benefit most or potentially least from TCBT and in demonstrating the advantages of TCBT being more cost-effective and feasible in clinical settings.

Future directions

Without doubt there is a very real issue relating to the unmet need for the treatment of anxiety and depression. It is likely that the solution to this will require a multi-modal approach, e.g., different modes of delivery (through the Internet or group treatments), training more practitioners (such the Improved Access to Psychological Therapies [IAPT] in the United Kingdom) and different approaches to treatment (of which TCBT may be one). In this regard, as described above, there does seem much to commend a transdiagnostic approach to treatment. Questions, however, remain. As described above, TCBT utilises many aspects of traditional CBT, and it is unlikely that TCBT will ever outperform DSCBT for people with a single disorder. It may, however, provide important advantages where symptoms are a mix of anxiety and depression or where there is comorbidity (although there is no substantive evidence about that currently). There is also a question about where TCBT may be best positioned in a stepped care approach to treatment. There is some suggestion that TCBT may be best used as one of the early steps before individual treatment and particularly where there are service constraints limiting access to treatment (although this has not been formally examined).

Conclusion

In conclusion, TCBT is a promising avenue to explore both from improving our understanding of anxiety and depressive symptoms and from developing effective, efficient and available treatments. The evidence to date is limited and does not suggest that it will be more effective than DSCBT or that DSCBT will become redundant, and it is likely that TCBT will have a complementary role to this, either in a stepped care approach or for particular patients in some settings.