 In the United Kingdom, a prevalence estimate of 1.0% based on the 2001 census meant that about half a million people aged five or older would have Tourette's, although symptoms in older individuals would be almost unrecognizable.During the 1990s, a more neutral view of Tourette's emerged, in which a genetic predisposition is seen to interact with non-genetic and environmental factors.TS was first included in the third revision of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-III) in 1980.