A Randomized, Double-blind, Placebo-controlled, Parallel Group Efficacy Study of Pramipexole and Placebo Administered Orally Over a 12 Week Treatment Phase in Parkinson's Disease Patients With Stable Motor Function and Depressive Symptoms

Parkinsons Disease (PD) is caused by a decrease of dopamine in a particular part of the brain. Dopamine is a messenger substance (neurotransmitter) that is used by the cells of the brain (nerve cells) to control and harmonize muscle movements. Consequently, the main manifestations of the disease affect movement and include tremor, muscular rigidity, slowness in performing movements and loss of balance. However, the disease affects also other, non motor functions and may cause other disorders, such as depression. Depression may be a reaction to the disability caused by the disease, but many studies show that depression is more common in PD than in other chronic debilitating illnesses. Moreover, there is also a biological explanation for the phenomenon: dopamine is also used in brain circuits involved in the experience of pleasure, and loss of pleasure in daily physical or social activity is one of the key manifestations of depression. The objective of the study is to assess whether pramipexole, at doses approved for the treatment of PD symptoms, is more effective than placebo in resolving depressive symptoms in PD patients. Also data on the safety of the product in the disease will be collected.