Evidence against a genetic relationship between Tourette's syndrome and anxiety, depression, panic and phobic disorders.

Analyses were undertaken to examine whether a wide range of psychiatric disorders, including anxiety, affective, substance abuse and psychotic disorders, represent variant manifestations of Tourette's syndrome (TS). Previous studies have suggested that chronic tics (CT) and obsessive-compulsive disorder (OCD) are variant expressions of TS since both CT and OCD are elevated among relatives of TS probands. In the current study, no other psychiatric disorder was significantly elevated among the relatives who did not have TS, CT or OCD when compared with a control sample. These findings are not consistent with the hypothesis that a wide range of psychiatric and behavioural disorders are variant expressions of TS.