The prognosis of Tourette syndrome: implications for clinical practice.

Tourette syndrome (TS) is a childhood-onset neuropsychiatric condition characterised by multiple motor and phonic tics. Comorbid behavioural problems are common, especially attention deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). Little is known about the long-term prognosis of TS, despite the need to inform patients about their possible clinical course and advise health care providers on clinical resource allocation strategies. This paper reviews the scientific literature on the prognosis of TS spanning the period 1990-2010. After searching three scientific databases, we identified seven original studies investigating the prognosis of TS. It is suggested that tic frequency and severity decline with age in a large proportion of patients (59-85%). Predictors of increased tic severity in adulthood include higher childhood tic severity, smaller caudate volumes and poorer fine motor control. Furthermore, the presence of untreated comorbid psychopathology, such as ADHD and OCD, can adversely affect the long-term outcome of patients with TS. Future studies on the prognosis of TS should be conducted on larger samples, both in community and clinical settings.