Neurocognitive Performance in Trichotillomania

Neuropsychological research indicates that trichotillomania (TTM), or hair pulling disorder, is associated with impaired cognitive flexibility and response inhibition. However, it is unclear how these neurocognitive deficits in TTM are related to symptom severity and what their implications are for treatment. The present study examined whether performance on tasks of cognitive flexibility and response inhibition were related to symptom severity, changed during treatment, and predicted treatment response in TTM. The current study utilized data from a randomized control trial comparing acceptance-enhanced behavior therapy (AEBT) to psychoeducation and supportive therapy (PST) in adults with TTM. Participants completed assessments at pre-treatment (n=88) and after 12 weeks of treatment (n=68). Cognitive flexibility was measured using the Object Alternation Task (OAT). Response inhibition was measured with the Stop Signal Task (SST). Results showed that higher TTM symptom severity was associated with poorer cognitive flexibility (r = .22, p = .045). Response inhibition was not related to symptom severity. Performance in either neurocognitive domain did not improve from pre- to post-treatment. Better response inhibition at pre-treatment predicted being a treatment responder in both treatment groups (OR = 0.55, p = .033). Cognitive flexibility did not predict treatment response. In conclusion, these findings support that cognitive flexibility and response inhibition are uniquely related to TTM symptom severity and treatment response in adults with TTM. The current results provide insight into the nature of neurocognitive functioning in TTM and have implications for treatment delivery and development. Limitations and future research directions are discussed.