A person who has tics does not necessarily have Tourette's disorder. Other disorders or medical conditions can cause tics.

• Transient tic disorder. A person with transient tic disorder has one or more motor and/or vocal tics. The tic occurs many times a day, nearly every day, for at least 4 weeks, but for no longer than 12 consecutive months. For this diagnosis, the tics must occur before the age of 18, and they cannot be caused by a substance or another condition.
• Chronic motor or vocal tic disorder. A person with chronic motor or vocal tic disorder has either motor or vocal tics, but not both. The tics occur many times a day and nearly every day, for more than 1 year. During this period, the person is not tic-free for more than 3 months. The tics start before the age of 18, and they cannot be caused by a substance or another condition.
• Tic disorders not otherwise specified. Nonspecific tic disorders are those that do not fall into any other of the tic categories. Examples include a tic that lasts less than 4 weeks or tics that start after the age of 18. "Secondary tourettism" is a term often used to describe tics that develop as a result of strokes, infection, injury, exposure to certain drugs or toxins, or conditions other than Tourette's disorder.