Cluster analytic methods have examined the symptom presentation of chronic
tic disorders (
CTDs), with limited agreement across studies. The present study investigated patterns, clinical correlates, and treatment outcome of
tic symptoms. 239 youth and adults with
CTDs completed a battery of assessments at baseline to determine diagnoses,
tic severity, and clinical characteristics. Participants were randomly assigned to receive either a comprehensive behavioral intervention for
tics (CBIT) or psychoeducation and supportive
therapy (PST). A cluster analysis was conducted on the baseline Yale Global
Tic Severity Scale (YGTSS) symptom checklist to identify the constellations of
tic symptoms. Four
tic clusters were identified: Impulse Control and Complex Phonic
Tics; Complex
Motor Tics; Simple Head Motor/
Vocal Tics; and Primarily Simple
Motor Tics. Frequencies of
tic symptoms showed few differences across youth and adults.
Tic clusters had small associations with clinical characteristics and showed no associations to the presence of coexisting psychiatric conditions. Cluster membership scores did not predict treatment response to CBIT or
tic severity reductions.
Tic symptoms distinctly cluster with little difference across youth and adults, or coexisting conditions. This study, which is the first to examine
tic clusters and response to treatment, suggested that
tic symptom profiles respond equally well to CBIT. Clinical trials.gov. identifiers: NCT00218777; NCT00231985.