Importance: Transdiagnostic interventions have been developed to address barriers to the dissemination of evidence-based psychological treatments, but only a few preliminary studies have compared these approaches with existing evidence-based psychological treatments.
Objective: To determine whether the Unified Protocol for Transdiagnostic Treatment of Emotional Disorders (UP) is at least as efficacious as single-disorder protocols (SDPs) in the treatment of anxiety disorders.
Design, setting, and participants: From June 23, 2011, to March 5, 2015, a total of 223 patients at an outpatient treatment center with a principal diagnosis of panic disorder with or without agoraphobia, generalized anxiety disorder, obsessive-compulsive disorder, or social anxiety disorder were randomly assigned by principal diagnosis to the UP, an SDP, or a waitlist control condition. Patients received up to 16 sessions of the UP or an SDP for 16 to 21 weeks. Outcomes were assessed at baseline, after treatment, and at 6-month follow-up. Analysis in this equivalence trial was based on intention to treat.
Interventions: The UP or SDPs.
Main outcomes and measures: Blinded evaluations of principal diagnosis clinical severity rating were used to evaluate an a priori hypothesis of equivalence between the UP and SDPs.
Results: Among the 223 patients (124 women and 99 men; mean [SD] age, 31.1 [11.0] years), 88 were randomized to receive the UP, 91 to receive an SDP, and 44 to the waitlist control condition. Patients were more likely to complete treatment with the UP than with SDPs (odds ratio, 3.11; 95% CI, 1.44-6.74). Both the UP (Cohen d, -0.93; 95% CI, -1.29 to -0.57) and SDPs (Cohen d, -1.08; 95% CI, -1.43 to -0.73) were superior to the waitlist control condition at acute outcome. Reductions in clinical severity rating from baseline to the end of treatment (β, 0.25; 95% CI, -0.26 to 0.75) and from baseline to the 6-month follow-up (β, 0.16; 95% CI, -0.39 to 0.70) indicated statistical equivalence between the UP and SDPs.
Conclusions and relevance: The UP produces symptom reduction equivalent to criterion standard evidence-based psychological treatments for anxiety disorders with less attrition. Thus, it may be possible to use 1 protocol instead of multiple SDPs to more efficiently treat the most commonly occurring anxiety and depressive disorders.
Trial registration: clinicaltrials.gov Identifier: NCT01243606.