Tourette's is defined as part of a spectrum of tic disorders, which includes provisional, transient and persistent (chronic) tics.
While the exact cause is unknown, it is believed to involve a combination of genetic and environmental factors.
Many individuals with Tourette's go undiagnosed or never seek medical care.
Among those who are seen in specialty clinics, attention-deficit hyperactivity disorder (ADHD) and obsessive–compulsive disorder (OCD) are present at higher rates.
They may have tics for several years before becoming aware of premonitory urges.
Children may suppress tics while in the doctor's office, so they may need to be observed while they are not aware they are being watched.
Some common tics are eye blinking, coughing, throat clearing, sniffing, and facial movements.
Tourette's does not adversely affect intelligence or life expectancy.
Tics may also occur in "bouts of bouts", which vary for each person.Chronic tic disorder was either single or multiple, motor or phonic tics (but not both), which were present for more than a year.The fifth version of the DSM (DSM-5), published in May 2013, reclassified Tourette's and tic disorders as motor disorders listed in the neurodevelopmental disorder category, and replaced transient tic disorder with provisional tic disorder, but made few other significant changes.There are no specific tests for diagnosing Tourette's; it is not always correctly identified because most cases are mild and the severity of tics decreases for most children as they pass through adolescence.Extreme Tourette's in adulthood, though sensationalized in the media, is a rarity; tics are often unnoticed by casual observers.