(PS2-78) Neurocognitive Performance in Trichotillomania Predicts Symptom Severity Pre- and Post-treatment

Introduction: Neuropsychological research shows that adults with TTM have impairments in some neurocognitive functions, specifically response inhibition and cognitive flexibility, compared to healthy counterparts However, it is unclear how these neurocognitive deficits are related to TTM severity and potential implications for treatment. The present study examined relationships between performance on response inhibition and cognitive flexibility tasks and TTM symptom severity. We also tested pre-treatment response inhibition and cognitive flexibility as predictors of treatment outcome.

Methods: This study analyzed data from a randomized controlled trial comparing acceptance-enhanced behavior therapy(AEBT) to psychoeducation and supportive therapy(PST) in adults with TTM. Participants completed assessments at baseline(n=88) and after 12 weeks of treatment, 68 participants completed measures (90% female, 10% male; M age= 36.4(SD=12.87), 81% White, 13% Black, 6% not reported). Cognitive flexibility was measured using the Object Alternation Task(OAT). Response inhibition was measured with the Stop Signal Task(SST). Measures of TTM severity included the self-report Massachusetts General Hospital Hairpulling Scale (MGH-HS) and independent evaluator-administered National Institute of Mental Health Trichotillomania Severity Scale (NIMH-TSS).

Results: Results showed that at baseline, poorer cognitive flexibility on the OAT was correlated with higher TTM severity on the NIMH-TSS (r=.23, p=.045) but not MGH-HS (r=.08, p=.472). Baseline response inhibition (SST) was not related to baseline TTM severity. Binary logistic regressions showed that better response inhibition at baseline (SST) predicted being a treatment responder at post-treatment (B=-0.01, SE=0.003, p=.033, Odds ratio[OR]=0.55). Linear regressions indicated that better response inhibition at baseline also predicted lower post-treatment TTM symptom severity on the MGH-HS (B= 0.03, p=.015) and NIMH-TSS (B=0.02, p=.004), regardless of treatment group. Cognitive flexibility did not predict treatment response or post-treatment symptoms (ps >.05).

Discussion: Response inhibition and cognitive flexibility are uniquely related to TTM symptom severity and treatment outcomes in adults with TTM. These findings have implications for treatment delivery and development, as our results suggest that response inhibition and cognitive flexibility may be important potential treatment targets. Addressing response inhibition deficits could improve treatment outcomes, while improving cognitive flexibility might indirectly improve TTM symptom severity. Overall, these results provide insight into the nature of neurocognitive deficits in TTM and contribute to a more comprehensive picture of the brain-behavior connection in TTM.