Tics

Tics are very common in children. They are often present for a limited period of time (transient tics) and typically remit or significantly improve before adulthood. The majority of people with tics do not seek medical attention. The prototypical tic disorder causing disability is Gilles de la Tourette syndrome (TS), a childhood–onset neuropsychiatric disorder predominantly characterized by fluctuating and persisting motor and phonic tics but also a wide array of complex symptoms, such as premonitory urges, echo– and coprophenomena, and a variety of comorbidities including attention deficit hyperactivity disorder (ADHD) and obsessive–compulsive disorder (OCD). The most conspicuous feature distinguishing TS from other movement disorders is preceding inner urges; hence, tics are often experienced as voluntary movements, performed to transiently relieve unpleasant premonitory sensations. A typical course in a TS patient would be the onset of motor tics around the age of 5; onset of vocal tics several months or a few years later, with a peak of symptoms between the ages of 8 and 12; and a marked decrease until early adulthood. Etiology is largely genetic with environmental factors probably playing a disease–modifying role. There is much overlap with OCD and ADHD both phenomenologically and genetically, but specific mutations have not been identified. Structural and functional differences in brain areas between TS patients and healthy controls predominantly point to a dysfunction of the basal ganglia (BG) with an imbalance in the dopaminergic system. In line with these findings, the most successful treatment options in TS encompass typical and atypical antipsychotics. Some patients also benefit from tetrahydrocannabinol (THC), botulinum toxin injections, or, rarely, deep brain stimulation. Behavioral treatment has also been promoted. However, tics wax and wane and naturally decrease in 80 % of TS patients after puberty. Moreover, patients commonly suffer more from comorbidities than from TS. Therefore, most patients do not require pharmacological treatment for tics but can benefit from psychoeducation. Attention deficit hyperactivity disorder Basal ganglia Cortico-striatal-thalamo–cortical Dopamine Diagnostic and Statistical Manual Diffusion–tensor imaging γ-Aminobutyric acid Globus pallidus externus Globus pallidus internus Habit reversal therapy International classification of diseases Methylphenidate Medium spiny neurons Obsessive–compulsive disorder Orbitofrontal cortex ediatric autoimmune neuropsychiatric disorder associated with streptococcal infections Transcranial magnetic stimulation