CLOCK and Parkinson disease: There are several potential causes of sleep disturbances in PD patients, including effects of CNS neurodegeneration and neuroinflammation, circadian clock disruptions, ‘classical’ PD motor symptoms leading to poor bed mobility, dopaminergic therapies and co‐morbid psychiatric symptoms (Breen et al., 2014; Chahine et al., 2017; Rye, 2003).