Effects of cognitive behavioral therapy for worry versus befriending therapy in individuals with persecutory delusions: a randomized trial

Abstract Background Worry is common and distressing in psychotic disorders, contributing to the onset and persistence of persecutory delusions. A previously developed 8-week manualized CBT-worry intervention has shown efficacy in treating persecutory delusions, compared with standard care. We aimed to test CBT-worry’s impact on persecutory delusions at 8-weeks, as previously reported, delusions at 24-weeks, and secondary clinical outcomes, relative to an active comparison therapy. Study Design A two-arm, assessor-blinded, randomized controlled trial was conducted. 62 adults with a non-affective psychotic disorder and current persecutory delusion were randomized to CBT-worry (n=32) or befriending (n=30). The preregistered primary clinical outcome was persecutory delusion severity. Outcomes were assessed at baseline, post-treatment (8-weeks) and at follow-up (24-weeks). Results Regarding primary outcomes, CBT-worry was not superior to befriending in treating persecutory delusions at post-treatment or follow-up (p’s>.05). For secondary exploratory outcomes, CBT-worry demonstrated superiority over befriending for self-reported worry (d=.26, p=.006), depression (d=.23, p=.018), perseveration (d=.21, p=.024), insomnia (d=.25, p=.01), and asocial beliefs (d=.23, p=.022) and assessor-rated affective symptoms (d=.36, p<.001) post-treatment. At follow-up, no significant between-group treatment effects were found after correction for multiple comparisons. Conclusions A brief CBT-worry intervention did not outperform befriending in the treatment of persecutory delusions. CBT-worry did, however, demonstrate significant benefit for affective symptoms post-treatment, compared to befriending. At follow-up, gains were maintained in CBT-worry but were also observed in befriending, minimizing group differences. Limitations include a small sample size, lack of a non-clinical control, and 20% drop-out. ClinicalTrials.gov (NCT04748679)