Tic
A tic is a sudden, repetitive, nonrhythmic motor movement or vocalization involving discrete muscle groups. Tics can be invisible to the observer, such as abdominal tensing or toe crunching. Common motor and phonic tics are, respectively, eye blinking and throat clearing.
Tic disorder
In the fourth revision of the DSM (DSM-IV-TR), tic disorders were classified as follows:DSM-5 was published in 2013, updating DSM-IV-TR, which was published in 2000. The following changes were made:The fifth revision of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-5), published in May 2013, classifies Tourette's and tic disorders as motor disorders listed in the neurodevelopmental disorder category.