TICs

Tics are sudden, rapid, recurrent, nonrhythmic movements or vocalizations. They can involve multiple muscle groups and may include facial grimacing, blinking, shoulder shrugging, throat clearing, or repetitive sounds. Tics are typically classified as motor tics or vocal tics. Onset commonly occurs in childhood, with a peak in early adolescence; many tics lessen or disappear in late adolescence, while others persist into adulthood.

Tic disorders are diagnosed based on clinical criteria and history. The most well-known is Tourette syndrome, defined by multiple motor tics and at least one vocal tic present at some time during the illness, with onset before age 18 and persisting for more than a year. Other tic disorders include persistent (chronic) motor or vocal tic disorder and provisional tic disorder, which are distinguished by the number and duration of tic types and the time course. Differential diagnosis includes stereotypies, chorea, myoclonus, and other movement disorders, as well as conditions with compulsive behaviors or tics as part of autism spectrum disorders or OCD.

The causes of tics are not fully understood but involve genetic susceptibility and dysfunction in cortico-basal ganglia-thalamo-cortical circuits, with neurotransmitter imbalances, particularly dopamine, implicated. Environmental factors such as stress, fatigue, illness, and excitement can exacerbate tics, while some individuals can temporarily suppress them.

Management emphasizes education and reassurance. Behavioral therapies, especially comprehensive behavioral intervention for tics (CBIT) and habit reversal training, are effective for many. Pharmacologic options include alpha-2 adrenergic agonists (guanfacine, clonidine) for children and antipsychotics (e.g., risperidone, aripiprazole) for troublesome tics. Botulinum toxin injections can help focal motor tics; deep brain stimulation may be considered for severe, refractory cases. Prognosis varies; many individuals experience improvement over time, though comorbid conditions such as ADHD or OCD may influence functioning.