Recent advances in clinical practice emphasize the utility of Unified Protocol for the Transdiagnostic Treatment of Emotional Disorders (UP) as an effective intervention for targeting core processes underlying comorbid disorders. This study aimed to evaluate changes in psychopathological risk factors associated with the construct of neuroticism (i.e., negative affect, anxiety sensitivity, experiential avoidance, intolerance of uncertainty) within the UP to adults already on an optimal and stable dose of selective serotonin reuptake inhibitors (SSRIs). In a randomized controlled trial, a total of 39 adults (M age= 27.51 (±8.43); 56.4 % female), on SSRIs with a diagnosis of comorbid anxiety and depressive disorder were randomly assigned to either UP+SSRI (n= 18) or continued SSRI-only (n= 21). Neuroticism dimensions were assessed at baseline, posttreatment, and 1-month follow-up. UP+SSRI condition demonstrated medium to large effect sizes for changes over time on facets of neuroticism including negative affect (Cohen d = 1.12, 95% CI [0.44, 1.80]), anxiety sensitivity (Cohen d = 1.21, 95% CI [0.53, 1.90]), experiential avoidance (Cohen d = 0.74, 95% CI [0.09, 1.04]), and intolerance of uncertainty (Cohen d = 1.66, 95% CI [0.93, 2.39]). Post hoc analyses showed reductions in variables that were maintained at follow-up. Results adds to the growing body of literature and provide cross-cultural support for the utility of UP in targeting pathological risk factors as adjuncts to SSRI. Implications for future studies and limitations are discussed.
