ABSTRACT
Tourette's syndrome is the archetypal hyperkinetic disorder with a range of other unwanted behaviours that have long led to beliefs in witchcraft or possession. In this chapter we shall examine the natural history of tics and tic disorder, the comorbid conditions that may accompany Tourette's syndrome and obfuscate research ®ndings, and the intertwined genetic and environmental factors. We shall also describe the condition's pathophysiology, neuropsychology, and neurochemistry. Finally, we shall review evidence for it as a syndrome of developmental delay, to which most children may in fact almost be subject in subclinical form, and shall refer to the possibly adaptive aspects of the disorder that may have served to maintain its presence in the genome.
