A tic is a rapid, recurrent motor movement or vocalization. The most commonly known tic disorder is Tourette syndrome, but persistent motor or vocal tic disorder and provisional tic disorder are other types of neurodevelopmental tic disorders.

All types of tic disorders begin before age 18, although they may wax and wane in intensity, leading to classification of simple or complex. However, tics typically improve throughout adulthood, but can be affected by environmental or internal factors.