A multiple baseline controlled trial of cognitive behavioral therapy for trichotillomania
Trichotillomania patients feel compelled to pull out hairs from one or more bodily areas, generally in an effort to reduce anxiety or regulate other emotions. Previous treatment studies have suggested moderate efficacy of clomipramine, and some behavioral techniques, especially habit reversal, but results have largely been weak. Rothbaum (1992) piloted a 9-week cognitive-behavioral treatment package with moderate success. In the present study, this package's efficacy was assessed in a controlled fashion using a multiple baseline across participants design with two sets of three participants each. Each client saved her hairs and mailed them to the author during baseline, then attended nine treatment sessions during which saved hairs and some psychological measures were collected. Then specific techniques were taught and practiced approximately according to Rothbaum's guidelines (1993). Visual inspection of the hair-pulling data suggests that Participants 1, 2, and 4 improved with treatment, although Participant 4's pulling had decreased dramatically before any treatment techniques were introduced. For Participants 3, 5 and 6, clear interpretation is difficult. Because disagreement among judges of single case data is common, and because the author might be unfairly biased toward seeing improvement, further analyses were introduced. For each participant, hairpulling during baseline was compared with that during treatment statistically using a program for continuous-assessment time series data from single participants (ITSACORR; Crosbie, 1993). Only Participants 4 and 5 improved significantly due to treatment. This statistical analysis is not sufficient alone, because it fails to take into account the controls introduced by the multiple baseline data. Measures of anxiety, depression, severity of the trichotillomania and associated impairment were taken at baseline, then compared with the same at the end of treatment, and at 1- and 3-months follow-up. The Wilcoxon matched pairs signed-rank test confirmed that, with one exception (significantly decreased impairment due to trichotillomania between baseline and 1-month follow-up), there were no significant changes. In sum, these results were modest and highly variable across participants. As such, they fail to provide reliable support for the efficacy of Rothbaum's (1992) treatment paradigm.