Causes of Tourette Syndrome

Although the cause has not been established, it appears to involve an imbalance in the function of neurotransmitters (chemical messengers in the brain), dopamine and serotonin. It is also likely to involve abnormalities in other neurotransmitter systems of the brain.

The brain

TS is a genetic condition that often runs in families, and can occur with co-occurring conditions such as Attention Deficit Hyperactivity Disorder (ADHD) and Obsessive Compulsive Disorder (OCD). The genetic cause of TS is complex as not one single gene has been identified to be the cause of the condition.

Brain scanning has revealed that there are some areas of the brain that appear to be different in individuals with TS, for example some structures in the basal ganglia part of the brain, and in the fronto-temporal brain areas.

Environmental factors

Research has shown that different environmental factors may, in some cases, contribute to the onset or affect the severity of TS. These include pregnancy and birth related problems such as complications during pregnancy, drinking alcohol or smoking during pregnancy, severe nausea and/or vomiting during the first trimester and premature low birth weight children.  The research which indicates this can be difficult to interpret and results in different studies have varied. In an individual case it is not possible to know what factors caused TS apart from genetics when others in the family have tics. 

PANDAS

PANDAS is an abbreviation for Paediatric Autoimmune Neuropsychiatric Associated with Streptococcal infections. This term describes a subset of children who have OCD and/or tic disorders such as TS, and in whom symptoms worsen following strep infections such as ‘strep throat’ and scarlet fever.

Symptoms

With PANDAS, children usually have a dramatic, ‘overnight’ onset of symptoms preceded by a strep throat infection. Symptoms might include: motor or vocal tics, obsessions, and/or compulsions. Associated symptoms include: mood changes, sleep problems, joint pain, urinary frequency and separation anxiety.

A sudden onset of symptoms is often followed by a slow, gradual improvement in symptoms. If they have another strep throat infection, symptoms can return just as suddenly and dramatically as they did before.

Cause

The exact cause behind this phenomenon is not yet known, although it is thought that the mechanism is similar to that of rheumatic fever – an autoimmune disorder triggered by strep throat infections. In the case of PANDAS and TS, it is believed that the antibodies produced to fight the strep throat infection mistakenly recognise and ‘attack’ a part of the brain called the Basal Ganglia, which is believed to be responsible for movement and behaviour. Thus the antibodies interact with the brain to cause tics and/or OCD.

Treatment

The treatment for children with PANDAS is exactly the same for children with OCD and/or Tourette Syndrome.
This information is from the National Institute of Mental Health website.