Dystonia is a rare neurological condition involving involuntary sustained muscle contractions that can produce twisting and repetitive movements or abnormal postures. While dystonia symptoms can be caused by environmental factors such as head trauma or certain medications, an increasing number of genetic causes have been identified. In addition, studies of individuals with dystonia reported an increase of psychiatric symptoms, particularly affective disorders and obsessive-compulsive disorders, but the cause of this comorbidity was unknown. Some researchers suggested this was due to shared genetic susceptibility, but most thought it was a reaction to a chronic debilitating condition. To test the shared genetic susceptibility hypothesis, we re-contacted individuals who had previously participated in the genetic linkage study and were found to be in families segregating the DYT1 mutation. The results of this study (Heiman et al, 2004), suggested that early-onset recurrent depression is a clinical expression of the DYT1 gene mutation. Results of a subsequent paper showed that obsessive-compulsive disorder is not a clinical expression of the DYT1 gene mutation (Heiman et al, 2007). We are currently investigating whether or not other psychiatric manifestations, particulary anxiety disorders, are related to the DYT1 mutation.