Is Depression a Symptom of Parkinson’s Disease?

Parkinson’s disease is far more complex than we knew just 10 or 20 years ago. In fact, clinicians like John Gorecki MD, increasingly view Parkinson’s as a “family” of conditions — distinguishing discrete processes and symptoms formerly lumped together under the Parkinson’s aegis.

That said, Parkinson’s expansiveness doesn’t mean it’s difficult to diagnose. In fact, Parkinson’s and related conditions carry an array of symptoms that, taken together, support such a diagnosis. Neurologists and other clinicians involved in the diagnosis and evaluation of Parkinson’s patients are increasingly attentive to the presence of a particular symptom — depression — that could serve as an early indicator (or even future predictor) of Parkinson’s disease.

Classic Parkinson’s Disease Symptoms

Parkinson’s is a common condition: According to the Parkinson’s Disease Foundation, more than 60,000 Americans are diagnosed with PD every year, and as many as 10 million people worldwide are afflicted at any given time. Given the disease’s chronic nature, long duration and often striking presentation, it’s no surprise that many “classic” Parkinson’s symptoms are widely recognized and understood. Some such symptoms include:

  • Tremor, particularly in the hands and fingers
  • Slow movements and rigid muscles
  • Impaired posture and speech
  • Cognitive impairment (dementia)
  • Sexual dysfunction and bladder control issues
  • Sleep problems
  • Swallowing problems and constipation

These symptoms arise and become more noticeable as the disease progresses.

Depression and Parkinson’s Disease

Depression is not a “classic” Parkinson’s disease symptom. In fact, it’s arguably the least-known and most often overlooked symptom. Nevertheless, the Parkinson’s Disease Foundation reports that as many as 60 percent of those diagnosed with Parkinson’s experience “mild or moderate depressive symptoms” at some point during the disease’s progression.

Parkinson’s-related depression may occur at any point, sometimes the patient has been formally diagnosed. It’s a physical process caused by disease-related changes to the brain, specifically the area responsible for producing the mood-regulating chemical serotonin and the frontal lobe, which is responsible for regulating higher-level brain functions like mood and impulse control. Parkinson’s patients typically have under-active frontal lobes and lower levels of serotonin than non-Parkinsonian peers.

Parkinson’s-related depression can affect the overall progression of the disease as well as the quality of life of those afflicted. In particular, depressive Parkinson’s patients report lower levels of satisfaction with everyday tasks, find such tasks more difficult, and (on average) begin chemical treatment for Parkinson’s-related motor symptoms earlier than patients without symptoms of depression.

Pharmaceutical Treatment and Cognitive Therapy

Like many other presentations of depression, Parkinson’s-related depression is treatable with commonly prescribed pharmaceuticals. There’s also evidence that cognitive behavioral therapy, used in conjunction with or independently of pharmaceutical treatment, may ameliorate symptoms and improve quality of life. In fact, patients who take steps to treat their depression symptoms may notice an improvement in their motor and cognitive symptoms as well.

More to Learn About Parkinson’s Disease

It is now clear that there’s a link between depression and Parkinson’s disease. Given the complexity of the family of conditions known as “PD,” it is also a foregone conclusion that other links and correlations will emerge in the years to come. Such discoveries will teach us more about Parkinson’s and related conditions — and could provide some measure of hope (or at least set reasonable expectations) for Parkinson’s sufferers and their families.