Does the unified protocol really change neuroticism? Results from a randomized trial

Neuroticism is associated with the onset and maintenance of a number of mental health conditions, as well as a number of deleterious outcomes (e.g. physical health problems, higher divorce rates, lost productivity, and increased treatment seeking); thus, the consideration of whether this trait can be addressed in treatment is warranted. To date, outcome research has yielded mixed results regarding neuroticism's responsiveness to treatment, perhaps due to the fact that study interventions are typically designed to target disorder symptoms rather than neuroticism itself. The purpose of the current study was to explore whether a course of treatment with the unified protocol (UP), a transdiagnostic intervention that was explicitly developed to target neuroticism, results in greater reductions in neuroticism compared to gold-standard, symptom focused cognitive behavioral therapy (CBT) protocols and a waitlist (WL) control condition. Patients with principal anxiety disorders (N = 223) were included in this study. They completed a validated self-report measure of neuroticism, as well as clinician-rated measures of psychological symptoms. At week 16, participants in the UP condition exhibited significantly lower levels of neuroticism than participants in the symptom-focused CBT (t(218) = -2.17, p = 0.03, d = -0.32) and WL conditions(t(207) = -2.33, p = 0.02, d = -0.43), and these group differences remained after controlling for simultaneous fluctuations in depression and anxiety symptoms. Treatment effects on neuroticism may be most robust when this trait is explicitly targeted.