Periodic changes in the number, frequency, type and location of the tics, and in the waxing and waning of their severity.
Symptoms can sometimes disappear for weeks or months at a time.
Onset before the age of 21. What is not recognized is that the control, which can be exercised anywhere from seconds to hours at a time, may merely postpone more severe outbursts of symptoms. People with TS often seek a secluded spot to release their symptoms after delaying them in school or at work. Typically, tics increase as a result of tension or stress, and decrease with relaxation or concentration on an absorbing task. The expression of symptoms covers a spectrum from very mild, to quite severe.