Depression is a common and challenging component of Parkinson’s disease (PD). Up to 70% of patients with PD experience depression. This clinical symptom is not only a result of PD, but a part of the condition itself. Study findings have shown that inflammation not only plays a part in the physical signs of PD, but is also involved in the development of depression. The increase in inflammatory mediators, such as cytokines, in PD is detectable before signs of PD begin. These mediators may serve as important biomarkers of PD that can be utilized to detect PD and allow early intervention.