How infection can lead to psychiatric problems
Scientists using mice have discovered how early exposure to a common type of bacterium can lead to psychiatric disorders. PANDAS (Paediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infection) causes problems such as obsessive-compulsive behaviour, ticks and Tourette syndrome. It was known that streptococcal infection could lead to psychiatric problems but it wasn’t clear how.
In this study researchers showed how a specific strain of streptococcus bacteria – GABHS – can cause PANDAS symptoms in mice. This common bacterium and causes sore throats, but in some people the body not only destroys the bacteria, but also attacks healthy tissue in the brain.
To investigate the link between GABHS and PANDAS the team immunised mice with an inactive form of the bacterium. They saw that the mice produced antibodies to the bacteria and went on to show repetitive behaviour similar to that seen in children with PANDAS. They also found that administering antibodies from the immunised mice into another set of mice could cause a similar psychiatric condition.
This work shows how ordinary infections in childhood can lead to psychiatric disorders later in life. It opens up the possibility of identifying children at risk, and finding ways to prevent GABHS exposure leading to the development of PANDAS.