Abstract
Cognitive Behavior Therapy for psychosis (CBTp) is an effective treatment resulting in small to medium effect sizes with regard to changes in positive symptoms and psychopathology. As a consequence, CBTp is recommended by national guidelines for all patients with schizophrenia. However, although CBTp was originally developed as a means to improve delusions, meta-analyses have generally integrated effects for positive symptoms rather than for delusions. Thus, it is still an open question whether CBTp is more effective with regard to change in delusions compared to treatment as usual (TAU) and to other interventions, and whether this effect remains stable over a follow-up period. Moreover, it would be interesting to explore whether newer studies that focus on specific factors involved in the formation and maintenance of delusions (causal-interventionist approach) are more effective than the first generation of CBTp studies. A systematic search of the trial literature identified 19 RCTs that compared CBTp with TAU and/or other interventions and reported delusions as an outcome measure. Meta-analytic integration resulted in a significant small to medium effect size for CBTp in comparison to TAU at end-of-therapy (k = 13; = 0.27). However, the comparison between CBTp and TAU after an average follow-up period of 47 weeks was not statistically significant (k = 12, = 0.16). When compared with other interventions, there was no significant effect of CBTp at end-of-therapy (k = 8; = 0.16) and after a follow-up period (k = 5; = −0.04). Comparison between newer studies taking a causal-interventionist approach (k = 4) and first-generation studies showed a difference of 0.33 in mean effect sizes in favor of newer studies at end-of-therapy. The findings suggest that CBTp is superior to TAU post-therapy in bringing about a change in delusions, but that this change may not be maintained over the follow-up period. Moreover, interventions that focus on causal factors of delusions seem to be a promising approach to improving interventions for delusions.
Highlights
Before Cognitive Behavior Therapy for psychosis (CBTp) was introduced in the early 1990s, there was much concern that targeting delusions directly was likely to make matters worse
Comparison of Studies that used a Causal-interventionist Approach and First-generation CBTp Studies at End-of-therapy In order to select newer CBTp studies, the first and the last author independently selected studies that stated in their introduction that they “used a causal-interventionist approach” or that they focused on “factors that are causally involved in the formation and maintenance of delusions.”
The effect of CBTp on delusions did not remain stable after an average follow-up period of 47 weeks
Summary
Before Cognitive Behavior Therapy for psychosis (CBTp) was introduced in the early 1990s, there was much concern that targeting delusions directly was likely to make matters worse. Meta-analysis CBTp: effects on delusions of learning (Jaspers, 1913) This view has been questioned by epidemiological studies that point to a continuum between normal and psychotic experiences (McGovern and Turkington, 2001; van Os et al, 2009) which indicates that normal reasoning could be involved in the formation and maintenance of delusional beliefs. This view, along with research on cognitive and emotional correlates of psychotic symptoms (Garety et al, 2001) has been one of the main suppositions upon which the systematic development of CBTp is based. A characteristic aspect of CBTp compared to other psychological interventions for psychosis (e.g., psychoeducation, skill trainings etc.) is that the therapist works directly with delusional beliefs, by challenging the beliefs suspected of triggering and maintaining them (e.g., beliefs about the self and others) and by questioning the delusional beliefs per se
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