Depression is known to be a common symptom of Parkinson’s disease, but remains untreated for many patients, according to a new study by Northwestern Medicine investigators in collaboration with the National Parkinson’s Foundation (NPF).

In fact, depression is the most prevalent non-motor symptom of Parkinson’s, a chronic neurodegenerative disorder typically associated with movement dysfunction.

“We confirmed suspicion that depression is a very common symptom in Parkinson’s disease. Nearly a quarter of the people in the study reported symptoms consistent with depression,” said Danny Bega, MD, ’14 GME, instructor in the Ken and Ruth Davee Department of Neurology and first author of the study. “This is important because previous research has determined that depression is a major determinant of overall quality of life.”

Using the NPS’s patient database, the investigators looked at records of more than 7,000 people with Parkinson’s disease. Among those with high levels of depressive symptoms, only one-third had been prescribed antidepressants before the study began, and even fewer saw social workers or mental health professionals for counseling.

The investigators then focused their analysis on the remaining two-thirds of patients with depressive symptoms who were not receiving treatment at the start of the study. Throughout a year of observation, less than 10 percent of them received prescriptions for antidepressants or referrals to counseling. Physicians were most likely to identify depression and advocate treatment for patients with the severest depression scores.

The findings were published in the Journal of Parkinson’s Disease.

“The majority of these patients remained untreated,” said Dr. Bega. “Still, the physician recognition of depression in this population was actually better than previous reports had suggested.”

However, recognition may be lower for the general population of patients with Parkinson’s disease – the patients in this study visited medical centers deemed “Centers of Excellence” by the NPF.

“Physicians must be more vigilant about screening patients for depression as part of a routine assessment of Parkinson’s disease, and the effectiveness of different treatments for depression in this population need to be assessed,” said Dr. Bega.