Parkinson's disease (PD) is a neurodegenerative disorder clinically characterized by motor dysfunctions due to progressive loss of dopaminergic neurons and a broad spectrum of non-motor symptoms. Interestingly, non-motor symptoms like depression, anxiety and psychosis are often present several years before the occurrence of classic motor features seriously affecting patient quality of life. Their presence is often misleading, delaying the correct diagnosis of PD. Despite its high incidence, the pathophysiology and aetiology of neuropsychiatric symptoms associated with PD remains unclear. Currently, a lot of interest lays in research looking for genetic predictors of motor and non-motor symptoms in PD. The availability of next-generation sequencing technology for genome, epigenetic and transcriptional analysis opens the door to a new way of studying multifactorial diseases like PD and their comorbidities. In this review we will present new insights in the genomic and epigenetic background of psychiatric comorbidity in Parkinson's disease.