title: Principal components analysis of a large cohort with Tourette syndrome.
abstract: BACKGROUND
  Tourette syndrome is a heterogeneous familial disorder for which the genetic mechanisms are unknown. A better characterisation of the phenotype may help identify susceptibility genes.
  
  
  OBJECTIVE
  To extend previous factor-analytic studies of the syndrome.
  
  
  METHODS
  Symptom data from 410 people with Tourette syndrome were included in agglomerative hierarchical cluster and principal components analyses.
  
  
  RESULTS
  Five factors were observed, characterised by: (1) socially inappropriate behaviours and other complex vocal tics; (2) complex motor tics; (3) simple tics; (4) compulsive behaviours; and (5) touching self. Individuals with co-occurring attention-deficit hyperactivity disorder had significantly higher factor scores on Factors 1 and 3, whereas individuals with co-occurring obsessive-compulsive disorder and behaviours had significantly higher factor scores for Factors 1-4.
  
  
  CONCLUSIONS
  These findings add to the growing body of evidence that Tourette syndrome is not a unitary condition and can be disaggregated into more homogeneous symptom components.
authors.affiliation: Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA.
authors.forename: Mary M
authors.initials: MM
authors.lastname: Robertson
authors.forename: Robert R
authors.initials: RR
authors.lastname: Althoff
authors.forename: Adam
authors.initials: A
authors.lastname: Hafez
authors.forename: David L
authors.initials: DL
authors.lastname: Pauls
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001289:Attention Deficit Disorder with Hyperactivity / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000209:etiology; D025341:Principal Component Analysis; D016728:Self-Injurious Behavior / Q000209:etiology; D020323:Tics / Q000209:etiology; D005879:Tourette Syndrome / Q000175:diagnosis*