Aetiology of Co-morbid Psychiatric Disorders In Dystonia: A Biopsychosocial Hypothesis

Dystonias are a heterogeneous group of movement disorders characterised by involuntary, sustained contraction of antagonist muscles that causes repetitive movements or abnormal postures. Dystonia is a rare condition. Nonetheless, it is important due to the high morbidity patient's experience. Much of this morbidity results from disability associated with dystonic movement. However, it is less recognised that the frequent occurrence of co-morbid psychiatric conditions (40 75% of patients) in dystonia contributes to the morbidity of dystonia. While the pathophysiological basis of dystonic movement has been extensively investigated, little research into the aetiology of co-morbid psychiatric disorders has been performed. Here, a literature review was undertaken to define what psychiatric disorders occur in dystonia and to find studies that could be synthesised into a BioPsycho-Social model of the aetiology of psychiatric disorders in dystonia. Current research supports the hypothesis that psychiatric disorders in dystonia result from both the underlying neurobiological abnormality and psychosocial factors associated with disability and disfigurement.