Two recent epidemiological studies based on physician surveys and public anouncements have suggested a frequency in male childen [of TS] of 1 in 1,500 to 1 in 1,000 (Burd et al., 1986; Caine et al., 1988). We felt that the frequency of TS would be more accurately determined by having a trained observer constantly monitor everyone in a defined population. In such a study where students were monitored almost daily for a period of 2 years, we observed a frequency of TS in school boys of 1 in 95, and in school girls of 1 in 759, for a combined frequency of 1 in 169 (Comings et al., 1990a) (p. 189). (Comings, D. E. & Comings, B. G. (1991). Clinical and genetic relationships between autism-pervasive developmental disorder and Tourette syndrome: A study of 19 cases. American Journal of Medical Genetics, 39(2), 180-91.)
A recent study has called attention to dramatic rises in autism. Several conditions associated with maturational delay or acceleration are associated with autism including Tourette’s, stuttering and left handedness. A relevant question would be whether these three conditions are also increasing, and increasing at the same rates.
If autism is part of an associated whole cluster of conditions increasing across the world, perhaps by understanding where exactly those increases are taking place we can narrow the situations that are responsible.