Is metacognitive therapy a superior treatment for major depressive disorder?
Randomised controlled psychotherapy studies are expensive and time consuming to run and most end in stalemate horse races between two therapies which differ mainly in the language and literature they cite to support their protocols. So, it is always exciting to find a study that claims superiority of one bona fide approach over another, especially when the other is a well-established treatment. Well this time, Danish researchers led by Pia Callesen and collaborating with metacognitive therapy progenitor Adrian Wells bring us a randomized controlled trial comparing metacognitive therapy (MCT) with Beckian cognitive behaviour therapy (CBT) for major depressive disorder. To date, there are multiple meta-analyses showing many effective psychotherapies for depression with none more so than any other (Cuijpers, 2017). Is this the study that pushes the boundaries of what’s possible?
174 adults with major depressive disorder were randomly assigned to either MCT or CBT. The number of sessions was not prescribed, but individuals could receive up to 24 sessions. I’m sure most readers know what CT involves, but for completion: it followed (Beck, Rush, Shaw, & Emery, 1979) Cognitive Therapy for Depression book supplemented with Melanie Fennel’s (1989) chapter from Cognitive Behaviour Therapy for Psychiatric Problems. CBT focused on identifying and testing automatic thoughts, behavioural experiments to increase behavioural activation and progressing to challenging negative core beliefs. MCT followed the chapter on depression from Wells' (2009) Metacognitive Therapy of Anxiety and Depression book. The attention training task (ATT) was practised in session, every session. The ATT is like a mindfulness of sounds task for people who hate mindfulness: within 10 minutes, there are 3 phases: 1) attending to ~3 sounds inside the room and ~3 outside the room, one at a time, in turn; 2) switching attention rapidly between each sound; and 3) attempting to simultaneously attend to all sounds. Clients are taught detached mindfulness – a kind of brief, specific mindfulness of ‘thought trigger’ exercise without typical meditation stylings (hypnotic delivery, prolonged adoption of a pose with sustained attention). Clients use detached mindfulness in response to initial rumination triggers to facilitate postponing rumination, which in turn helps test beliefs about the uncontrollability of rumination. Other relatively distinctive foci are beliefs about intractable causes of depression (e.g., “depression is a brain disease”) and positive beliefs about maladaptive coping strategies (e.g., “sleeping more will help me feel better”, “it is better to expect the worst than be disappointed by thinking optimistically”).
There were no differences on the Hamilton Rating Scale of Depression, an independent assessor-rated scale, at least partly due to floor effects. However, on the client self-reported Beck Depression Inventory, MCT recipients experienced significantly greater improvements in depression symptoms than CT recipients, both at the end of treatment, and at 6-month follow-up, with 74% MCT group meeting recovery criteria compared with 52% CBT at end of treatment (74% and 56% respectively at follow-up). You might think it sounds like the authors are cherry-picking their results, but there is a well-established disparity between observer-rated and self-report measures for depression (Minami, Wampold, Serlin, Kircher, & Brown, 2007) where observer-rated scales tend to be more sensitive to change than self-report ones. I’m sure it’s a complete coincidence that antidepressant trials predominantly use assessor-rated scales as their gold standard. But the point is, achieving a significant difference on the BDI-II is, in fact, the more difficult achievement.
The study had a number of strengths. Cognitive therapy for depression is a strong comparison condition for MCT as the emergent therapy. The authors measured treatment credibility and working alliance at session 3 and found no differences between treatments. There were no differences in adherence and if anything, CBT therapists were rated as more competent than MCT therapists. There were no significant differences in completion rates (77% MCT, 68% CBT). On secondary outcomes, there were no differences between treatments on measures of anxiety (BAI), Young schema questionnaire, but MCT recipients showed larger improvements in metacognitive beliefs and dysfunctional attitudes. MCT group required fewer sessions (5.5 v 6.7 on average), which was statistically significant, even if only marginally practically significant.
So what’s the fine print? There were only two therapists in the study and the MCT therapists were supervised closely by the inventor. That’s a quality of supervision most readers are unlikely to be able to access. Oh, and each therapist completed about 6 training cases in the approach prior to commencing in the trial. Another study would be needed to see if comparable results could be obtained without having 6 complete practice cases with the inventor of the approach before “counting” the results. Just saying. They excluded people with psychosis, bipolar disorder, substance abuse, organic brain syndrome, all of which are very standard exclusions. They also excluded people with learning difficulties, borderline personality disorder, people who had received CBT or MCT before, or who were pregnant or close to giving birth. 100 were excluded (those analysed represent 63.5% of those initially assessed), 78% of which did not have depression as the primary problem. After those exclusions, the sample remained somewhat mild. Approximately 40% of the sample had a BDI in the severe depression range at baseline. To put this in context, at CTAD, out of the 234 clients we allocated to students from 2010-2016 who screened positive for major depressive disorder, 54% were in the severe range on the BDI. The staff would have seen a much higher proportion of severe depression.
Highlighting these limitations is not intended to discredit the results achieved by MCT, but if you are a practitioner reading this, consider: 1) how many of those excluded conditions you routinely screen for (if you were to mentally calculate your effectiveness, would you exclude 36% of people seeking treatment for depression before you started counting how many were improving?); and 2) if you are looking for a new approach to assist with a case of treatment-resistant depression, just note that unless you failed to try CBT or MCT with your client, that this study is no guide as to whether its results would generalise to your case. On the other hand, if you are fluent with MCT already but have mainly used it for GAD (for which it was first developed), and you have clients with primary major depressive disorder and who do not meet these exclusion criteria, this study suggests MCT would be a good first-line treatment to try, and could potentially treat the client quite rapidly, without needing to address schema content.
Take home: Clinical Implications
Metacognitive therapy is a good first-line psychotherapy for major depressive disorder, if:
You are competent in MCT
Your client clearly has major depressive disorder as their main complaint
Your client doesn’t have bipolar disorder, psychosis, substance abuse, organic brain syndrome, learning difficulties, borderline personality disorder and isn’t pregnant
Your client hasn’t already tried CBT or MCT before
Go to https://www.nature.com/articles/s41598-020-64577-1 for the original article (open access).