Association and Familial Coaggregation of Idiopathic Dystonia with Psychiatric Outcomes

Background Psychiatric comorbidities are common and major determinants of quality of life in idiopathic dystonia. Their prevalence estimates from service-based studies are heterogeneous. Objective We explored the association between idiopathic dystonia and depressive disorders, anxiety disorders, suicide attempts, and death by suicide using Swedish population-based registers. Methods Diagnoses of idiopathic dystonia and psychiatric outcomes from inpatient and outpatient specialist services (1997-2013) were collected from the National Patient Register and the Cause of Death Register. Familial associations were explored using the Multi-Generation Register. Adjusted logistic regression analyses measured associations with psychiatric disorders in individuals with dystonia compared with general population individuals and their unaffected siblings, as well as in full siblings of individuals with dystonia compared with full siblings of unaffected individuals. Results Individuals with dystonia were more likely than those without to have a diagnosis of depressive disorder (adjusted odds ratio = 2.00, 95% confidence interval: 1.77-2.26), anxiety disorder (adjusted odds ratio = 2.13, 95% confidence interval: 1.90-2.39), and suicide attempts/death by suicide combined (adjusted odds ratio = 1.80, 95% confidence interval: 1.50-2.17), with odds higher in most idiopathic dystonia forms. In the full sibling comparison, estimates followed the same pattern, with overall attenuated magnitude. Full siblings of individuals with dystonia had higher likelihood of depressive or anxiety disorders and suicide attempts/death by suicide combined compared with siblings of individuals without dystonia. Conclusions Different forms of idiopathic dystonia confirm its association with increased risk for depressive and anxiety disorders and suicide attempts. Familial coaggregation of dystonia and these psychiatric comorbidities supports shared genetic and extragenetic factors. (c) 2020 International Parkinson and Movement Disorder Society