Comorbidity in trichotillomania (hair‐pulling disorder) : a cluster analytical approach
Date
2019
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
Background: A promising approach to reducing the phenotypic heterogeneity of psychiatric disorders involves the identification of homogeneous subtypes. Careful
study of comorbidity in obsessive‐compulsive disorder (OCD) contributed to the
identification of the DSM‐5 subtype of OCD with tics. Here we investigated one of
the largest available cohorts of clinically diagnosed trichotillomania (TTM) to determine
whether subtyping TTM based on comorbidity would help delineate clinically
meaningful subgroups.
Methods: As part of an ongoing international collaboration, lifetime comorbidity data
were collated from 304 adults with pathological hair‐pulling who fulfilled criteria for
DSM‐IV‐TR or DSM‐5 TTM. Cluster analysis (Ward's method) based on comorbidities
was undertaken.
Results: Three clusters were identified, namely Cluster 1: cases without any comorbidities
(n = 63, 20.7%) labeled “simple TTM,” Cluster 2: cases with comorbid major depressive
disorder only (N = 49, 16.12%) labeled “depressive TTM,” and Cluster 3: cases
presenting with combinations of the investigated comorbidities (N = 192, 63.16%) labeled
“complex TTM.” The clusters differed in terms of hair‐pulling severity (F = 3.75,
p = .02; Kruskal–Wallis [KW] p < .01) and depression symptom severity (F = 5.07,
p = <.01; KW p < .01), with cases with any comorbidity presenting with increased severity.
Analysis of the temporal nature of these conditions in a subset suggested that TTM
onset generally preceded major depressive disorder in (subsets of) Clusters 2 and 3.
Conclusions: The findings here are useful in emphasizing that while many TTM patients
present without comorbidity, depression is present in a substantial proportion
of cases. In clinical practice, it is crucial to assess comorbidity, given the links demonstrated
here between comorbidity and symptom severity. Additional research is
needed to replicate these findings and to determine whether cluster membership
based on comorbidity predicts response to treatment.
Description
CITATION: Lochner, C., et al. 2019. Comorbidity in trichotillomania (hair‐pulling disorder) : a cluster analytical approach. Brain and Behavior, 9(12):e01456, doi:10.1002/brb3.1456.
The original publication is available at https://www.nature.com
Publication of this article was funded by the Stellenbosch University Open Access Fund
The original publication is available at https://www.nature.com
Publication of this article was funded by the Stellenbosch University Open Access Fund
Keywords
Compulsive hair pulling, Borderline personality disorder, Comorbidity
Citation
Lochner, C., et al. 2019. Comorbidity in trichotillomania (hair‐pulling disorder) : a cluster analytical approach. Brain and Behavior, 9(12):e01456, doi:10.1002/brb3.1456