Depression in Parkinson's disease is a very common symptom. The combination of PD and Depression and the associated cluster of symptoms can make it especially difficult to effectively treat Depression in PD. Recent research is strongly suggesting that in many ways Depression can be considered a disease of the brain, meaning the depressed person with PD has 2 neurological disorders not just one! In one study researchers measured the size of the hippocampus in patients with and without depression and found that those who suffer from depression demonstrated marked hippocampus shrinkage over time. Further, their research indicated that early and successful treatment of depression with anti-depressant medication prevented this shrinkage from occurring and in fact in some cases could stimulate brain cell growth. For more information about this and other studies related to mental and emotional health issues check out the great PBS series "This Emotional Life: In Search of Ourselves.....and Happiness."