Tics and Tourette's syndrome in childhood.

Childhood tics are multidimensional in nature. The dimensions run along various continuums, including duration of symptoms (from fewer than 1 year to lifelong), intensity of symptoms (from mild to severe), frequency of symptoms (from rare to constant), variety of symptoms (from single motor groups/single phonic tic to multiple occurrences of both types), complexity of tics (from simple motor/phonic tic to multiple motor groups or the production of multiple sounds, including involuntary phrases), response to treatment (from good to minimal or no response), and comorbid psychiatric disorders (from none to multiple). This review describes these dimensions and their relationships to the current diagnostic scheme for tic disorders.