Children with PANDAS are clinically identified by dramatic, "overnight" onset of symptoms, including motor or vocal tics, obsessions, and/or compulsions, although this has not been consistent in all studies. However these differences are often the case with a disease based solely upon a clinical description. Indeed some studies have shown no acute motor exacerbations among clinically defined PANDAS subjects whilst others have shown a profound one.
In addition to the motor symptoms, it is also thought that children may have psychiatric manifestations, becoming moody, irritable or show concerns about separating from parents or loved ones. This abrupt onset is hypothesized to be preceded by a strep throat infection. The clinical spectrum of PANDAS appears to resemble that of Tourette's syndrome which has lead some researchers to hypothesize that PANDAS and Tourette's may have some association, although this is highly speculative and controversial.