years, and with the incidence of new-onset tic disorders decreasing in the teen years. New
onset of tic symptoms in adulthood is exceedin gly rare and is often associated with expo-
sures to drugs (e.g., excessive cocaine use) or is a result of a central nervous system insult
(e.g., postviral encephalitis). Although tic onse t is uncommon in teenagers and adults, it is
not uncommon for adolescents an d adults to present for an initial diagnostic assessment
and, when carefully evaluated, provide a histor y of milder symptoms dating back to child-
hood. New-onset abnormal move ments suggestive of tics out side of the us ual age range
should result in evaluation for other move ment disorders or for specific etiologies.