Parkinson's disease (PD) depression may be a biological part of the disease itself, resulting from PD-related changes in brain chemistry. Untreated depression and other mood disorders can have a greater impact on well-being than even common motor symptoms.

Depression affects at least 50 percent of people with PD sometime in the course of their disease, but it is often under-recognized and, therefore, under-treated, even though effective treatments exist, both pharmacologic and nonpharmacologic. Treating depression can be a significant way to improve quality of life.

Veronica Bruno, MD, MPH, a neurologist specializing in movement disorders at the University of Calgary in Alberta, Canada, a Parkinson's Foundation Center of Excellence, discusses depression, the problem of under-diagnosis, and the benefits of recognition and treatment.