Depression and anxiety are common in disease to have important consequences on quality of life. These have long been recognized as frequent accompanying syndromes, and several reports suggest that these are the causative process or risk factors that are present many years before the appearance of motor symptoms. The neurochemical changes involving dopamine, norepinephrine, and serotonin might be related to the pathophysiology of depression and anxiety, but this is still not clear. Several studies showed that anxiety patients occur earlier than depression, during the premotor phase, suggesting that there may be a link between the mechanisms that cause anxiety. Whereas a recent study reported that patients with depression and anxiety were associated with different demographic and clinical features.
