However, symptoms are an individual phenomenon, with people exhibiting many different symptoms, perhaps over the course of their lifetime.
Tics are experienced as an irresistible urge (as, for example, in a sneeze) and must eventually be expressed.
However, the evidence supporting such a link is not conclusive at this stage.
In terms of cause, genetic studies show that TS is inherited as a gene or genes, there being a 50% risk of the gene being transmitted with each separate pregnancy.
For a diagnosis of TS to be made, the onset of symptoms must be before the age of 18 years.
Once the tic has been performed, until it feels ‘just right’, a sense of relief is then experienced.
The estimated incidence of this ranges from 35% to 50%.
The incidence of TS in OCD is lower (5% to 7%), although tics are reported in 20% to 30% of individuals with OCD.
Complex motor tics include jumping, smelling, touching rituals, and self-injurious behaviour.
Coprolalia (vocalising offensive words and phrases), Echophenomena (repeating a sound) and Echolalia (repeating a word or phrase just heard) constitute complex vocal tics.
Many people try and suppress their tics until they can find a secluded spot in which to release them.