Effects of Cognitive Behavioral Therapy for Worry Versus Befriending Therapy in Individuals with Persecutory...

Worry is common and distressing in psychotic disorders, contributing to the onset and persistence of persecutory delusions. A previously developed 8-week manualized cognitive behavioral therapy (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.

A two-arm, assessor-blinded, randomized controlled trial was conducted. Sixty-two 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).

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.

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).