Tourette syndrome (TS) is a neurological condition that first appears in childhood and is characterised by motor and vocal tics (1). Tics are involuntary, rapid, repetitive, intermittent motor movements or sudden, uncontrolled vocal sounds. Tics often occur in children and are normally transient. The TS diagnosis is often employed when at least two motor tics and one or more vocal tics have been present, not necessarily at the same time, for more than a year. In the case of TS, tics usually first appear at age 5–6 and are most intense at age 10–12 (1). Most population-based studies of TS are small, and estimates of its prevalence vary considerably (2). In a meta-analysis of prevalence studies, a mean prevalence of 0.77 % was found (2). The studies were mainly conducted in Europe and North America and comprised children aged 6–15 years. The prevalence was higher for boys than girls, with an average boy-girl ratio of 4.2 (2).
Studies based on health registry data have demonstrated a lower prevalence of Tourette syndrome than studies based on a representative sample of the population. In Denmark, 0.4–0.5 % of all children receive the diagnosis before the age of 15, whilst the corresponding prevalence in Finland is 0.1–0.2 % and less than 0.1 % in Sweden (3). The diagnostic practice in Norway has never been examined.
Genetic predisposition is the most important known risk factor for Tourette syndrome (4). In studies of twins and families, the heritability is calculated at 77 %. The pathogenesis has not been clarified but MR studies indicate that people with TS have functional disturbances in the neural pathways between the cerebral cortex and the basal ganglia (1). The majority of people with TS also have other neurological or psychiatric conditions (1). In childhood and adolescence, hyperkinetic disorder (ADHD) and obsessive-compulsive disorder (OCD) are the most common comorbidities (1, 4). Behavioural problems and anger issues are common, and emotional distress often occurs in adolescence. More than one-third are assumed to have outgrown TS by adulthood, while the other conditions often persist (1).
The best-documented non-medication form of therapy is tics management training (5), which is also the first-choice therapy. This is cognitive behavioural therapy where you learn to resist the tic urge. In addition, it incorporates relaxation techniques and psychosocial interventions. If the tics cause pain, social and emotional problems or make it difficult to function normally at school and in daily life, drugs therapy may be an option (6). However, there are only small studies of drugs therapy and only a few have been conducted as randomised, double-blind and placebo-controlled trials.
The European clinical guidelines for treating Tourette syndrome recommend risperidone, an atypical antipsychotic drug, as the first choice of treatment (7). Aripiprazole, a newer atypical antipsychotic drug, is also reported as promising. Clonidine, an antiadrenergic drug, is recommended for combined treatment of TS and ADHD. In Norway, regional guidelines have been drawn up for the Southern and Eastern Norway Regional Health Authority, and the recommendations are in line with the European guidelines (6). Aripiprazole and clonidine can be reimbursed on individual application, but this only applies to children, not adults. Risperidone is not reimbursed.
In this study, we used data from the Norwegian Patient Registry in order to calculate the percentage of children and adolescents receiving the TS diagnosis for the country as a whole, and by county. We also examined any other psychiatric and neurological diagnoses these children and adolescents receive. By combining data from the Norwegian Patient Registry and the Norwegian Prescription Database, we examined the use of psychopharmaca and other medications that affect the central nervous system. The analyses were initiated by the Autism and Tourette's committee, a government-appointed body that was established in 2018 to assess the range of services to people with autism spectrum disorders and Tourette syndrome.