Increased Risk of Parkinson's Disease in Patients With Schizophrenia Spectrum Disorders.

Schizophrenia spectrum disorder increases the risk of PD later in life. This association was observed in both individual patient data and nationwide register data. Therefore, despite the opposite dopaminergic disease mechanisms, schizophrenia spectrum disorder increases rather than decreases the risk of PD. The increased PD risk could be related to risk-altering effects of dopamine receptor antagonists or to the increased vulnerability of the dopamine system induced by illness phase-dependent dopamine dysregulation in schizophrenia/schizophrenia spectrum disorder. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.