In an invited commentary (Moritz et al. Reference Moritz, Werner, Menon, Balzan and Woodward2016), the developers of metacognitive training (MCT) have challenged the results of the meta-analysis on the efficacy of MCT on positive symptoms, delusions and data gathering bias (van Oosterhout et al. Reference van Oosterhout, Smit, Krabbendam, Castelein, Staring and van der Gaag2015). The recommendation of this meta-analysis was not to implement MCT in routine care at this moment, because of a lack of evidence.
In their introduction (Moritz et al. Reference Moritz, Kerstan, Veckenstedt, Randjbar, Vitzthum, Schmidt and Woodward2011) refer to another meta-analysis by Jiang et al. (Reference Jiang, Zhang, Zhu, Li and Li2015) quoting significant effects for positive symptoms (as well as for delusions without the study by van Oosterhout et al. Reference van Oosterhout, Krabbendam, de Boer, Ferwerda, van der Helm, Stant and van der Gaag2014). The van Oosterhout et al. (Reference van Oosterhout, Krabbendam, de Boer, Ferwerda, van der Helm, Stant and van der Gaag2014) study is a negative study, but it is the largest randomized controlled trial (RCT) and indeed was rated as the study with the lowest risk of bias by Jiang et al.; it is not clear why one would discard the best study to date? The developers could usefully be referred to the conclusion in the abstract of Jiang et al.: ‘The limited number of RCT trials, the variability of the method and time of the outcome evaluation, and methodological problems in the trials make it impossible to come to a conclusion about the effectiveness of MCT for schizophrenia. More randomized trials that use standardized outcome measures, that use intention-to-treat (ITT) analyses, and that follow-up participants at regular intervals after the intervention are needed to determine whether or not MCT should become a recommended adjunctive treatment for schizophrenia.’ In our opinion this conclusion is the same as ours.
In their rebuttal the developers apply four headings with different arguments; these are addressed below.
Studies omitted
Moritz et al. note that some studies were omitted; we reran our analyses including the appropriate studies. We added the data of Aghotor et al. (Reference Aghotor, Pfueller, Moritz, Weisbrod and Roesch-Ely2010); Moritz et al. (Reference Moritz, Kerstan, Veckenstedt, Randjbar, Vitzthum, Schmidt and Woodward2011) and Gaweda et al. (Reference Gaweda, Krezolek, Olbrys, Turska and Kokoszka2015). We found the data in the meta-analysis of Eichner (Reference Eichner2015), a PhD student of Moritz, who was kind enough to provide the data via Research Gate. We discarded two non-randomized studies: an extremely negative study by Rocha & Queirós (Reference Rocha and Queirós2013) and an extremely positive study by Erawati et al. (Reference Erawati, Keliat, Helena and Hamid2014).
It is not accurate to say that we omitted the So et al. (Reference So, Chan, Chong, Wong, Lo, Chung and Chan2015) study from our paper because it had not been published – or accepted for publication – at the point our meta-analysis was accepted for publication.
However, we have added this study in our reanalysis.
The results of the reanalysis demonstrate that there are some significant effects for positive symptoms (g = 0.32) and delusions (g = 0.31), but not for data gathering (g = 0.11) if all the studies are considered. However, the findings from the high-quality and intention-to-treat data are similar to our original results with no significant effects on delusions, positive symptoms or data gathering.
Heterogeneity and moderator analysis
We chose to conduct some additional moderator analyses with the high-quality studies and not the low-quality studies as Moritz et al. suggest. Van Oosterhout et al. (Reference van Oosterhout, Krabbendam, de Boer, Ferwerda, van der Helm, Stant and van der Gaag2014) is the largest study with the lowest risk of bias, but is a negative study. It does not make sense to remove robust studies from an analysis only to remove heterogeneity.
MCT+ is not CBT
The authors (Moritz et al. Reference Moritz, Veckenstedt, Randjbar, Vitzthum and Woodward2011 b) wrote in the paper on MCT+ that ‘Individualized metacognitive therapy (MCT+) followed group sessions according to the general guidelines for CBT (e.g. Fowler et al. Reference Fowler, Garety and Kuipers1995).’ As Fowler is one of the founding fathers of CBT for psychosis, this led us to conclude that MCT+ is based on CBT. In the same paper it is stated: ‘MCT … is grounded on the principles of CBT (Fowler et al. Reference Fowler, Garety and Kuipers1995) and basic research on cognitive biases in schizophrenia (for reviews, see Garety & Freeman, 1999; Freeman et al. 2007), as well as deficits in social cognition/theory of mind (Frith, 1994; Frith & Corcoran, 1996).’ CBT in psychosis has included work on cognitive biases for over a decade. The main difference seems to be that MCT is set up like a course targeting transfer of ‘cold cognitions’, while CBT focuses on personalizing and experiencing the effects of biases in real life. In doing so, CBT is rather aimed at modifying ‘hot cognitions’.
Evolution of MCT
Moritz and colleagues suggested changing the inclusion criteria to patients without severe delusions. We have checked the baseline data of the studies on delusions. The three studies with the highest baseline delusion scores were So et al. (Reference So, Chan, Chong, Wong, Lo, Chung and Chan2015), Favrod (Reference Favrod, Rexhaj, Bardy, Ferrari, Hayoz, Moritz, Conus and Bonsack2014) and van Oosterhout et al. (Reference van Oosterhout, Krabbendam, de Boer, Ferwerda, van der Helm, Stant and van der Gaag2014). Taking these three studies, the effect size is 0.49, while studies with the lowest delusion scores at baseline (Moritz et al. Reference Moritz, Kerstan, Veckenstedt, Randjbar, Vitzthum, Schmidt and Woodward2011 a,b, Reference Rocha and Queirós2013; Briki et al. Reference Briki, Monnin, Haffen, Sechter, Favrod, Netillard and Vandel2014; Gaweda et al. Reference Gaweda, Krezolek, Olbrys, Turska and Kokoszka2015) have a pooled effect size of 0.25 on delusions. So the empirical evidence rather suggests that patients with highest baseline scores of paranoia in general benefit most from therapy.
In summary, we appreciate the opportunity to air these differences in opinion; but have to conclude that the best available evidence suggests that MCT is not yet at a stage to advocate its routine use. That is to say, we acknowledge Moritz et al.'s position that MCT is work in progress and this progress needs to be data driven. However, including less rigorous evidence into a meta-analysis may offer a different opinion, but this is probably not the most robust scientific way forward.
Declaration of Interest
None.
