A systematic review and discussion of symptom specific cognitive behavioural approaches to delusions and hallucinations
Introduction
Cognitive Behaviour Therapy for psychosis (CBTp) is an accepted, adjunct psychological therapy for individuals suffering from distressing psychotic symptoms. The main instrument of change in CBTp involves reframing appraisals and modifying behavior related to psychotic symptoms, to reduce distress and improve functioning and well-being. Therapy is collaborative, based on a shared formulation, and uses a normalizing philosophy (Morrison and Barratt, 2010). It is geared towards achieving the person's personal valued goal(s), with paramount importance being given to the therapeutic relationship and empowerment, maintaining the person's self-esteem, and providing hope (Brabban et al., 2017). Due to the heterogeneity of presentation in psychosis, a range of therapy approaches have been developed, reflected in the many books and manuals currently available (see Johns et al., 2014).
Randomized controlled trials (RCTs) of CBTp have tended to comprise composite CBTp approaches for heterogeneous groups of patients, addressing different types of symptoms. To date, there have been > 20 meta-analyses reviewing up to 50 RCTs. The effect sizes across these meta-analyses range from 0.09 (Velthorst et al., 2015) to 0.93 (Gould et al., 2001), depending on the permutations of trials included, for instance whether they focused on specific populations (e.g., treatment resistant patients, Burns et al., 2014), type of therapy (e.g., formulation-based therapies, van der Gaag et al., 2014), outcomes (e.g., negative symptoms, Lutgens et al., 2017), assessment time-point (e.g., end of therapy, Jauhar et al., 2014), or comparison group (e.g., active control, Turner et al., 2014). For the primary outcome (generally an overall symptomatology measure) the average effect is in the small to moderate range (d = 0.40; Wykes et al., 2008), with smaller effects in methodologically rigorous trials (Jauhar et al., 2014).
However the value of combining highly heterogeneous trials with different foci has been questioned (Byrne, 2014, Peters, 2014), since such analyses reflect an over-simplification of the complexities of psychosis presentations and of the range of psychological interventions encompassed within a broad CBTp framework (Thomas, 2015). Meta-analyses focusing on individually tailored, formulation-based approaches (van der Gaag et al., 2014), and reporting effect sizes for individual symptoms (Mehl et al., 2015, Naeem et al., 2016, van der Gaag et al., 2014), have been more informative about the specific effects of CBTp on delusions and hallucinations. These analyses are consistent in showing small-to-moderate effect sizes for hallucinations (0.44, van der Gaag et al., 2014; 0.45, Naeem et al., 2016) and delusions (0.36, van der Gaag et al., 2014; 0.56 Naeem et al., 2016), although the results are less consistent for the smaller number of trials comparing CBTp with other psychological interventions (Turner et al., 2014).
One limitation is that even in the meta-analyses reporting effect sizes on specific symptoms, the studies selected were not necessarily RCTs where the therapy focused on a particular symptom, but included mostly trials with heterogeneous patients and generic CBTp approaches, with secondary outcome measures of delusions and hallucinations. The findings may therefore underestimate effects, since the studies may not have been powered for the secondary outcomes. Moreover, it is possible that presenting symptoms may not have been targeted by the therapy, depending on the individual's goals. One meta-analysis looking at outcomes on delusions (Mehl et al., 2015) compared generic CBTp approaches to newer studies taking a ‘causal-interventionist approach’ (Freeman, 2011). They found a difference of 0.33 in mean effect sizes in favor of the newer studies, where patients were selected for the presence of persecutory delusions, the therapy focused specifically on hypothesized maintenance factors, and the primary outcomes assessed the actual focus of therapy.
In this paper, we review and discuss the empirical evidence for ‘targeted’ studies on delusions and hallucinations; i.e., trials that evaluate components of generic CBTp focusing on specific symptoms. In order to facilitate the interpretation of any differences in outcome, we sought to increase the comparability of studies in terms of the type of interventions used, and only included studies where the approach was entirely individualized to the patient rather than relying on a manualized training approach or being group-based; the therapy focused on formulating and changing either hallucinations or delusions, or factors closely associated with the symptom, such as distress (e.g. hallucination related distress), behavior (e.g. acting on hallucinations), or maintenance process (e.g., worry); and the primary outcome(s) reflected the focus of therapy. Third wave and ‘new’ approaches were included if they exhibited similar goals to CBTp, i.e., disrupting the associations between the presence of psychotic symptoms and their emotional and behavioural sequelae, even if the ‘road-map’ to achieving these changes diverged from traditional CBTp. As the number of studies was small and studies differed in the type and intensity of the intervention employed, we opted for a discursive review rather than a quantitative effect-integration. This approach is more suitable when the main aim is to reflect on the differences between therapeutic approaches and their outcomes and to derive implications for future research.
Section snippets
Method
Suitable peer-reviewed articles in English were identified in March 2017 by conducting two separate literature searches (delusion- and hallucination-focused) in electronic databases (MEDLINE and PsycINFO) via Ovid. The following search terms were used:
(“CBT”, “cognitive behavio*”, or “cognitive-behavio*”, or “intervention”, or “therapy”, or “training” or “treat*” or “trial”) were either combined with (“delusion”, or “paranoia”) or with (“hallucination* or voice*”).
Moreover, reference lists of
Results
The literature search revealed 507 peer-reviewed studies for delusions and 1293 for hallucinations after removing duplicates. After the selection process (see Fig. 1), four studies on delusions and six on hallucinations met the full inclusion criteria. A further two studies were trial protocols at the time of the literature search, but were published during the revision process and thus included, making a total of eight RCTs for hallucinations. Details on studies, including sample sizes, target
Discussion
This review synthesized research evaluating the effect of targeted, individualized cognitive behavioural interventions focusing specifically on delusions and hallucinations. This research strategy is in its infancy, with only 12 studies adopting this approach, of which nine were pilot trials. Nevertheless, the results are highly promising. All trials reported effect sizes against treatment-as-usual above d = 0.4 on at least one primary outcome at post-therapy and several effects in the large
Role of funding source
This work was not funded by external organizations.
Conflict of interest
Tania Lincoln has written treatment manuals and given paid workshops on cognitive behavior therapy for psychosis. Emmanuelle Peters is the Director of a specialist psychological therapies service for psychosis patients (Psychological Interventions Clinic for outpatients with Psychosis; PICuP), South London and Maudsley NHS Foundation Trust, which also provides training. Other than that neither of the authors have a conflict of interest including any financial, personal or other relationships
Contributors
Both authors contributed to the manuscript in equal proportions and have approved the final manuscript.
Acknowledgment
The authors thank Sandra Opoka, M.Sc. for her help with the data-extraction from the primary studies.
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