Tics are repetitive, brief, jerky motor movements and/or vocalizations. Any part of the body can be affected but common visible sites include the face (e.g. blinking, grimacing, chin-protruding, clearing one’s throat, or making other vocalizations) and upper body (e.g., moving one’s neck to the side, shoulder, and limb movements). The assessment of tics can be difficult as they naturally wax and wane over time, and are also commonplace in a subclinical form, especially in young people. In fact, one of the authors of this book was trained to look for subtle perinasal tics by an experienced OCD psychiatrist when he was a medical student, and now sees tics wherever he goes. While subclinical tics are common (up to 15% of children), however, formal Tic Disorders are more rare, ranging from 0.5% (Tourette’s Syndrome) through to up to 6% (Transient Tic Disorder) in children and adolescents. Adult Tic Disorders are considerably rarer.
Motor tics typically precede vocal tics by one or two years, and tics in general peak during late childhood and adolescence (aged 10-20 years), often with a marked reduction in severity into early adulthood. Where tics start in adulthood (a form of Tic Disorder not otherwise specified), symptoms are more functionally impairing and difficult to treat. Tics can increase during times of extreme emotion, and reduce with voluntary effort (in some individuals) and when concentrating on intricate tasks. They can be preceded by sensory experiences or urges and followed by relief.