(PS8-C64) Neuroticism Change Varies as a Function of Skill Module Ordering and Treatment Length Conditions in the Unified Protocol

Neuroticism accounts for the development and maintenance of a range of anxiety and depressive disorders; thus, targeting this trait directly may provide a more efficient approach to addressing emotional disorders (Barlow et al., 2014). Previous research suggests that most of the change in neuroticism as a function of treatment occurs early and that treatments longer than eight weeks do not invoke greater change (Roberts et al., 2017). However, researchers have not determined whether prioritizing specific cognitive-behavioral skills have a more robust effect on neuroticism, nor have they determined the optimal treatment length for addressing this trait. Using data from a sequential multiple assignment randomized trial (SMART) evaluating personalized delivery of the Unified Protocol, a transdiagnostic intervention developed to address neuroticism, we sought to whether change in neuroticism differs as a function of treatment length or sequencing of skills presented. Specifically, in the parent study, participants were randomly assigned to receive modules of the UP in an order that prioritized patient strengths, compensated for weaknesses, or in the standard published order. Following the fifth therapy session, patients underwent a second-stage randomization in which they were assigned to either discontinue treatment after their sixth session (brief treatment condition) or complete the full twelve sessions (full treatment condition). We explored whether (a) participants in the brief condition maintain gains garnered across the first six sessions, continue to improve, or worsen during the follow-up period, and (b) participants in the full condition continue to improve across the entire 12 sessions. Additionally, we explored whether (c) there are changes in the extent to which neuroticism improves as a function of skill sequencing condition. We used piecewise linear mixed-effects models with a linear spline to examine change in neuroticism as a function of treatment length conditions (brief and full). We fit a linear model for each combination of ordering and treatment duration condition (e.g., standard order and brief treatment, standard order and full treatment, etc.) using ordering condition (strengths, weakness, standard) as a moderator in these models. Results show varying patterns of change in neuroticism across module ordering and treatment length conditions such that those in the capitalization condition evidenced greater change in neuroticism before the second-stage randomization, whereas those in the standard condition showed greater change following the second-stage randomization. These findings provide preliminary evidence that change in neuroticism may occur more quickly when patient skill strengths are prioritized.