To the best of our knowledge the current study is the first randomized controlled trial that has examined the efficacy of any treatment for pediatric TTM, and its findings are encouraging with respect to the potential clinical utility of BT. BT was superior to MAC at post-treatment; moreover, acute treatment gains in BT were on average maintained over the course of an eight-week maintenance phase and through a naturalistic follow-up period. The absence of evidence for relapse following BT alone contrasts somewhat with findings from adult trials of behavioral approaches that included awareness training, stimulus control, and competing response procedures,35,36
and provides some preliminary support for the possibility that treatment of TTM during childhood or adolescence may be associated with more durable outcomes than does treatment during adulthood. Recent examinations of TTM phenomenology across the developmental spectrum have indicated a preponderance of automatic pulling in children and adolescents relative to focused pulling, which is not the same pattern typically observed in adults.37
Thus, it could be the case that treating TTM with BT before it takes on more complex affect regulation functions may be why treatment gains appear to be more robust and durable in the current sample than has been observed in the adult TTM treatment literature.4
In light of such developmental considerations, we also performed secondary analyses on the current sample to explore whether treatment outcome differences could be observed between the younger children and the older children who received behavior therapy in the current sample. A mixed model ANOVA, discussed in detail elsewhere,38
indicated that children ages 7–9 experienced comparable symptom reduction to the children ages 10–17 based on the NIMH-TSS; moreover, visual inspection of the plotted NIMH-TSS data between week 0 and week 8 suggested greater symptom reduction among the younger participants. Although low statistical power precludes drawing definitive conclusions, these findings suggest that even manualized BT can be tailored to the child’s appropriate developmental level.
The current sample is notable for phenomenological similarity to a sample collected as part of the Child-Adolescent Trichotillomania Impact Project,8
especially with respect to the pulling site information: scalp hair was by far the most common pulling site in both groups, followed by eyebrows and eyelashes. These two samples differed though in the number of active pulling sites reported: 57% of the CA-TIP sample reported more than one active pulling site, whereas only 33% of the current sample did. It is notable that the mean age of the current sample is about two years younger than reported for the CA-TIP sample. It is possible that the difference in the number of current pulling sites reflects a developmental trajectory for TTM in that the vast majority (97%) of the adult sample from the TIP reported multiple current pulling sites. Data on pulling styles collected from clinical samples across the full developmental spectrum will be critically important to examine in order to look at whether there are differences in the predominance of focused pulling (pulling with full awareness of the behavior and a clearly identifiable affective trigger) versus automatic pulling (pulling outside of awareness), as these different styles of pulling may necessitate different intervention strategies. New instruments have been developed for use with adults39
that will facilitate a careful examination of the relationship between pulling styles and treatment outcome.
There are, of course, many limitations to what can be learned from a small treatment development project given its inherently restricted budget, duration, and scope. First, the small sample size of the present study limits the degree to which strong conclusions can be drawn about treatment effects. Second, while the MAC condition did control for the effects of repeated assessments and for the non-specific effects of participating in a clinical trial, it failed to account for the potential effects of therapist contact time, psychoeducation about TTM, and patient and parent expectancies of outcome. Third, the naturalistic follow-up period was relatively short, included only a subset (75%) of those who had been randomized to BT, and three of the four BT participants who did not complete a follow-up assessment had been week 8 non-responders, so it is possible that the data on durability of gains overestimate the long-term benefits of BT. Fourth, the absence of a treatment outcome measure adapted specifically for use with younger samples raises questions about the validity of conclusions; work is currently underway to examine the psychometrics of the NIMH-TSS with developmental adaptations to the language used to solicit information about pulling behavior and related phenomena (e.g., urges). Finally, information about pulling style in this sample was not collected, and thus the potential for differential response to BT depending on the preponderance of focused versus automatic pulling cannot be determined. A psychometrically sound measure of pulling style among children and adolescents with TTM has since been created,40
and will be valuable in the search for moderators and mediators of treatment response. Our research group is now taking the next steps to address some of these key limitations in the context of an ongoing NIMH-funded project41
in which we have: 1) increased the sample size from 24 in the present RCT to 60 or more in the ongoing study, which will allow us to observe whether the BT outcome can be replicated in a larger sample; 2) included an active comparison condition (Psychoeducation/Supportive Counseling) that will control for therapist contact time, psychoeducation, and other non-specific factors to ascertain whether the encouraging outcome achieved in the current trial is due to the specific components of the BT protocol; and 3) continued to treat and formally evaluate patients who receive open BT following participation in the control treatment, to permit greater statistical power to explore moderators and mediators of outcome, including pulling styles as measured by the Milwaukee Inventory of Styles of Pulling – Child Version (MIST-C).40
Recent encouraging findings for NAC in adults,16
a glutamate modulator, now open a potential avenue for exploration of its efficacy and safety in youth. Future studies should examine the relative and combined efficacy of BT and NAC, which would provide further information to guide clinical practice for the fairly large number of youth who suffer from TTM.