(PS10-B45) Increased Psychological Flexibility Predicts Long-term Treatment Outcomes for Trichotillomania

Introduction

Acceptance-enhanced behavior therapy (AEBT-TTM; Woods & Twohig, 2008) is an empirically supported treatment for TTM that combines traditional behavior therapy with acceptance and commitment therapy (ACT). A core adaptive process of ACT is enhanced psychological flexibility, which is the ability to choose behaviors based on personal values and goals while staying in contact with the present moment. Prior research on ACT-enhanced treatments for depression (Pots et al., 2016) and OCD (Twohig et al., 2015) identified increased psychological flexibility as a mechanism of change associated with durable treatment effects, but this process has not been examined in AEBT-TTM. Considering the high relapse rates seen in TTM treatment (Falkenstein et al., 2014), it is imperative to identify change processes associated with long-lasting improvements in TTM. Thus, the present study examined whether changes in psychological flexibility are associated with long-term treatment outcomes for AEBT-TTM as compared to a therapeutic control condition.

Methods

This study used six-month follow-up data from a randomized control trial comparing AEBT-TTM to a psychoeducation and supportive therapy (PST) control. A total of 85 adults with TTM were randomized to receive 10 sessions of either AEBT or PST across 12 weeks. Participants (M age = 35.4) mostly identified as female (92%; 8% male) and Caucasian (82%; 13% African American; 3.5% did not identify race). The self-report Acceptance and Action Questionnaire – Trichotillomania (AAQ-TTM) was used to measure psychological flexibility. Independent evaluators administered the National Institute of Mental Health Trichotillomania Severity Scale (NIMH-TSS) and the Clinical Global Impressions-Improvement (CGI-I) scale. The self-report Massachusetts General Hospital-Hairpulling Scale (MGH-HS) was also used to evaluate symptom severity. CGI-I scores of “very much improved” or “much improved” determined clinical response status.

Results

In the AEBT group, increased AAQ-TTM from baseline to post-treatment was a significant predictor of symptom improvement from baseline to follow-up on the MGH-HS (b=.329, SE=.116, p=.008) and NIMH-TSS (b=.223, SE=.089, p=.013). AAQ-TTM also predicted responder status at follow-up in the AEBT group (B=.107, SE=.044, p=.015). For the PST group, improved AAQ-TTM was related to change in NIMH-TSS score from baseline to follow-up (b=0.209, SE=.086, p=.021), but was not associated with change on the MGH-HS or responder status at follow-up (ps > .05).

Discussion

These findings indicate that increased psychological flexibility is a significant predictor of long-term TTM symptom improvement and treatment response for AEBT-TTM. This study provides support that psychological flexibility is a mechanism of change through which AEBT-TTM exerts its benefits and long-term effects. As relapse is common in TTM treatment studies, these results provide important insight into a key process to target in TTM interventions. It may be valuable for future research to identify specific AEBT components that enhance psychological flexibility. Research should also continue to examine other mechanisms of change and gain maintenance in treatments for TTM.