[Diagnosis and therapy are still challenging, despite the rapid growth of knowledge].

Psychiatric diagnoses are not reflections of the aetiology of the disorder, but rather lists of symptoms with considerable overlaps, which hamper research and may cause confusion. The diagnoses of autism spectrum disorder, attention deficit hyperactivity disorder and tic disorder are often comorbid along with a number of other symptomatic syndromes. Individual immune responsivity is possibly involved in pathophysiological mechanisms.