Depressive symptoms in Parkinson's disease.

Depression occurs in approximately 45% of all patients with Parkinson's disease (PD), does not correlate with the stage of motor deficits, reduces quality of life independently of motor symptoms and appears to be underrated and undertreated. Anxiety and depression are the risk factors for the development of PD and may be present many years before the appearance of motor symptoms. Studies using functional imaging techniques indicate a primary relationship between depression and PD. Because of overlapping clinical symptoms, the diagnosis is mainly based on subjectively experienced anhedonia and feelings of emptiness. Serotonergic, noradrenergic and dopaminergic mechanisms play key roles in the aetiology of depression in PD. Tricyclic and newer selective antidepressants including serotonin and noradrenaline reuptake inhibitors appear to be effective in treating depression in PD. Selective reuptake inhibitors seem to be better tolerated because of their favourable side-effect profile. Experimental and clinical investigations indicate antidepressive effects for pramipexole. Placebo-controlled studies showed antidepressant effects of pramipexole in patients with different forms of depression. Various studies show that pramipexole improves depression in addition to motor symptoms in patients with PD. Because of the data available as well as clinical reasoning, pramipexole may be used as a first-line treatment in patients with PD and depression.