The Gilles de la Tourette syndrome: the current status.

Gilles de la Tourette syndrome (GTS) is characterised by multiple motor and one or more vocal/phonic tics. GTS was once thought to be rare, but many relatively recent studies suggest that the prevalence is about 1% of the worldwide community, apart from in Sub-Saharan Black Africa. Comorbidity and coexistent psychopathology are common, occurring in about 90% of clinical cohorts and individuals in the community. The most common comorbidities are attention deficit hyperactivity disorder, obsessive-compulsive behaviours, and disorder, and autistic spectrum disorders, while the most common coexisting psychopathologies are depression, anxiety and behavioural disorders such as oppositional defiant and conduct disorder. There has been an increasing amount of evidence to show that the quality of life in young people is reduced when compared with normative data or healthy control populations. It is widely accepted that most cases of GTS are inherited, but the genetic mechanisms appear much more complex than previously understood, as evidenced by many recent studies; indeed, there have been suggestions of 'general neurodevelopmental genes' which affect the brain development after which the 'specific GTS gene(s)' may further affect the phenotype. Other aetiopathogenetic suggestions have included environmental factors such as neuro-immunological factors, infections, prenatal and peri-natal difficulties and androgen influences. Few studies have addressed aetiology and phenotype, but initial results are exciting. The search for endophenotypes has followed subsequently. Intriguing neuroanatomical and brain circuitry abnormalities have now been suggested in GTS; the most evidence is for cortical thinning and a reduction in the size of the caudate nucleus. Thorough assessment is imperative and multidisciplinary management is the ideal. Treatment should be 'symptom targeted', and in mild cases, psycho-education and reassurance for the patient and the family may be sufficient. Behavioural treatments such as Comprehensive Behavioural Intervention for Tics including Habit Reversal Training have been shown to be significantly better than other behavioural/psychological treatments and 'placebo'. Medication is often necessary for moderately affected individuals. In more severe cases, medical treatment is not simple and referral to an expert may be advisable. In general, neuroleptics and clonidine or guanfacine are the medications of choice for the tics. Other treatments which may be needed for loud and severe phonic tics include botulinum toxin. In severe adult GTS patients who are refractory to medication and other therapies, deep brain stimulation looks promising.