Principal components analysis of a large cohort with Tourette syndrome.

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.

AIMS

To extend previous factor-analytic studies of the syndrome.

METHOD

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.