“Studies by our group and others have shown that relatives of patients with Parkinson’s disease have an increased risk of Parkinson’s disease,” explains Walter Rocca, M.D., senior author of the study and a Mayo Clinic neurologist and epidemiologist. “Recently, we showed they also have increased risk of essential tremor and of cognitive impairment or dementia. However, their risk of psychiatric disorders was unknown.

“Because many patients with Parkinson’s disease develop anxiety and depression after and even before the onset of the disease, we explored whether this tendency was present to a greater extent in family members of people with Parkinson’s disease compared with people without the disease. We found that, indeed, relatives of patients with Parkinson’s disease are at increased risk for anxiety and depressive disorders, which suggests a genetic or other relationship between those disorders and Parkinson’s disease.”

Dr. Rocca emphasizes that the familial susceptibility factors may be genetic, environmental or a combination of the two, and that further research is needed to determine their exact nature.