Psychiatric disorders in primary focal dystonia and in Parkinson's disease

Background: Primary focal dystonia and Parkinson's disease are movement disorders that have contrasting motor phenotypes. The aim of this study was to compare the frequency and the severity of psychiatric disorders in primary focal dystonia and Parkinson's disease. Methods: Two groups of 30 patients matched by gender and age underwent a neurological and psychiatric assessment. Results: Parkinson's disease patients were diagnosed with higher rates of major depression (P = 0.02) and generalized anxiety disorder (P = 0.02), and greater severity of depressive symptoms (P = 0.04), while patients with primary focal dystonia exhibited increased severity of obsessive-compulsive symptoms (P = 0.02). Discussion: The difference in pathophysiology of primary focal dystonia and Parkinson's disease may explain the different psychiatric profiles of these two diseases. The increased frequency of affective symptoms in Parkinson's disease may be related to the fact that Parkinson's disease is a neurodegenerative disease marked by the loss of monoaminergic neurons which does not happen in primary focal dystonia. Conclusion: The psychiatric profile differs in movement disorders with distinct neurobiological bases.