Most studies of TS involve males, who have a higher prevalence of TS than females, and gender-based differences are not well studied; a 2021 review suggested that the characteristics and progression for females, particularly in adulthood, may differ and better studies are needed.Most adults with TS have mild symptoms and do not seek medical attention. While tics subside for the majority after adolescence, some of the "most severe and debilitating forms of tic disorder are encountered" in adults. In some cases, what appear to be adult-onset tics can be childhood tics re-surfacing. Co-occurring conditions
Because people with milder symptoms are unlikely to be referred to specialty clinics, studies of Tourettes have an inherent bias towards more severe cases. When symptoms are severe enough to warrant referral to clinics, ADHD and OCD are often also found. In specialty clinics, 30% of those with TS also have mood or anxiety disorders or disruptive behaviors. In the absence of ADHD, tic disorders do not appear to be associated with disruptive behavior or functional impairment, while impairment in school, family, or peer relations is greater in those who have more comorbid conditions. When ADHD is present along with tics, the occurrence of conduct disorder and oppositional defiant disorder increases. Aggressive behaviors and angry outbursts in people with TS are not well understood; they are not associated with severe tics, but are connected with the presence of ADHD.
In teenagers and adults with an abrupt onset of tics and other behavioral symptoms, a urine drug screen for stimulants might be requested.Increasing episodes of tic-like behavior among teenagers (predominantly adolescent girls) were reported in several countries during the COVID-19 pandemic. Researchers linked their occurrence to followers of certain TikTok or YouTube artists. Described in 2006 as psychogenic, abrupt-onset movements resembling tics are referred to as a functional movement disorder or functional tic-like movements. Functional tic-like movements can be difficult to distinguish from tics that have an organic (rather than psychological) cause. They may occur alone or co-exist in individuals with tic disorders. These tics are inconsistent with the classic tics of TS in several ways: the premonitory urge (present in 90% of those with tics disorders) is absent in functional tic-like movements; the suppressibility seen in tic disorders is lacking; there is no family or childhood history of tics and there is a female predominance in functional tics, with a later-than-typical age of first presentation; onset is more abrupt than typical with movements that are more suggestible; and there is less co-occurring OCD or ADHD and more co-occurring disorders.