Depression is a mood disorder in which overwhelming feelings of sadness, loss and hopelessness interfere with a person’s ability to function at home or work. There are many causes of depression, including psychological, biological and environmental factors. But in people with Parkinson’s disease (PD), an imbalance of certain neurotransmitters (brain chemicals) that regulate mood is thought to play a major role. Like tremor and other motor symptoms of PD, depressive symptoms can be improved with medications. The following factors can contribute to the development of depression in Parkinson’s.
- Negative thoughts. Negative thoughts and attitudes about living with a chronic illness can lead to feelings of sadness, helplessness and hopelessness. Dwelling on these feelings may make a person more vulnerable to depression.
- Social isolation. The lack of a supportive social network that results from a more restricted lifestyle, such as early retirement or loss of independence, can make depression more likely.
- History of mental health issues. Research suggests many Parkinson’s sufferers experience depression or anxiety two to five years before the diagnosis of PD, which may mean that depression is not simply a psychological reaction to the illness, but a part of the underlying disease process.
- Changes in the brain. Parkinson’s disease and depression affect the same physical parts of the brain involved in thinking and emotion. Also, both conditions affect the levels of three important neurotransmitters (dopamine, serotonin and norepinephrine) that influence mood and movement.
- Severe stress. People who are diagnosed with a chronic illness often get depressed. For some people, the ongoing distress of coping with such a life crisis triggers the disorder.
Side effects from drugs. Certain prescription drugs can cause symptoms that mimic depression.
Page reviewed by Dr. Joash Lazarus, NPF Movement Disorders Fellow, Department of Neurology at Emory University School of Medicine.