Immunological factors are increasingly recognized as etiologically important in a range of neuropsychiatric disorders, such as autism spectrum disorder,1 schizophrenia,2 or bipolar disorder.3 The potential link between immunological factors and psychiatric symptoms has been much debated in obsessive-compulsive disorder (OCD) and Tourette's/chronic tic disorders (TD/CTD), due to the still controversial link between group A streptococcus infections and the abrupt onset of these psychiatric symptoms in a small group of children.4, 5
