title: Cluster analysis of the Yale Global Tic Severity Scale (YGTSS): symptom dimensions and clinical correlates in an outpatient youth sample.
abstract: Tic disorders are heterogeneous, with symptoms varying widely both within and across patients. Exploration of symptom clusters may aid in the identification of symptom dimensions of empirical and treatment import. This article presents the results of two studies investigating tic symptom clusters using a sample of 99 youth (M age = 10.7, 81% male, 77% Caucasian) diagnosed with a primary tic disorder (Tourette's disorder or chronic tic disorder), across two university-based outpatient clinics specializing in tic and related disorders. In Study 1, a cluster analysis of the Yale Global Tic Severity Scale (YGTSS) identified four symptom dimensions: predominantly complex tics; simple head/face tics; simple body tics; and simple vocal/facial tics. In Study 2, these clusters were shown to be differentially associated with demographic and clinical characteristics. Findings lend support to prior research on tic phenomenology, help to organize treatment goals, and suggest symptom dimensions of tic disorders for further evaluation.
authors.affiliation: Department of Psychology, University of California-Los Angeles, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095-1563, USA. kkir@ucla.edu
authors.forename: Katharina
authors.initials: K
authors.lastname: Kircanski
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Woods
authors.forename: Susanna W
authors.initials: SW
authors.lastname: Chang
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Ricketts
authors.forename: John C
authors.initials: JC
authors.lastname: Piacentini
mesh_terms: D000293:Adolescent; D002648:Child; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D008297:Male; D010045:Outpatients; D012720:Severity of Illness Index; D013981:Tic Disorders / Q000175:diagnosis* / Q000503:physiopathology
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