Psychological Medicine



The prevalence of Gilles de la Tourette syndrome in children and adolescents with autism: a large scale study


S. BARON-COHEN a1c1, V. L. SCAHILL a1, J. IZAGUIRRE a1, H. HORNSEY a1 and M. M. ROBERTSON a1
a1 Department of Experimental Psychology and Psychiatry, University of Cambridge; Children's Centre, Southport; and Department of Psychiatry and Behavioural Sciences, University College London and the National Hospital for Neurology and Neurosurgery, London

Abstract

Background. An earlier small-scale study of children with autism revealed that 8·1% of such patients were co-morbid for Gilles de la Tourette syndrome (GTS). The present study is a large scale test of whether this result replicates.

Method. Four hundred and forty-seven pupils from nine schools for children and adolescents with autism were screened for the presence of motor and vocal tics.

Results. Subsequent family interviews confirmed the co-morbid diagnosis of definite GTS in 19 children, giving a prevalence rate of 4·3%. A further 10 children were diagnosed with probable GTS (2·2%).

Conclusions. These results indicate that the rate of GTS in autism exceeds that expected by chance, and the combined rate (6·5%) is similar to the rates found in the smaller-scale study. Methodological considerations and alternative explanations for an increased prevalence are discussed.


Correspondence:
c1 Address for correspondence: Dr Simon Baron-Cohen, Departments of Experimental Psychology and Psychiatry, University of Cambridge, Downing Street, Cambridge CB2 3EB.


Metrics