How is TS diagnosed?

TS is a diagnosis that doctors make after verifying that the patient has had both motor and vocal tics for at least 1 year.  The existence of other neurological or psychiatric conditions[1] can also help doctors arrive at a diagnosis.  Common tics are not often misdiagnosed by knowledgeable clinicians.  But atypical symptoms or atypical presentation (for example, onset of symptoms in adulthood) may require specific specialty expertise for diagnosis. There are no blood or laboratory tests needed for diagnosis, but neuroimaging studies, such as magnetic resonance imaging (MRI), computerized tomography (CT), and electroencephalogram (EEG) scans, or certain blood tests may be used to rule out other conditions that might be confused with TS.

It is not uncommon for patients to obtain a formal diagnosis of TS only after symptoms have been present for some time. The reasons for this are many.  For families and physicians unfamiliar with TS, mild and even moderate tic symptoms may be considered inconsequential, part of a developmental phase, or the result of another condition.  For example, parents may think that eye blinking is related to vision problems or that sniffing is related to seasonal allergies.  Many patients are self-diagnosed after they, their parents, other relatives, or friends read or hear about TS from others.