Hypothesis III. Tourette syndrome is only one of several causes of a developmental basal ganglia syndrome.

Tourette syndrome (TS) is a hereditary condition characterized by the presence of chronic, multiple motor tics and is commonly associated with obessive-compulsive behavior, attentional and executive dysfunction, and aggressive behavior. A wide range of other genetic and environmental conditions that interfere with normal basal ganglia developmental processes can produce a clinical syndrome that we call the developmental basal ganglia syndrome (DBGS), and which closely resembles TS. Failure to distinguish TS from other causes of DBGS has probably hampered research efforts aimed at clarifying the neurobiological mechanisms, localizing the genetic defect, assessing therapy, and establishing accurate prevalence rates for TS.