November 4, 2014

The Parkinson's / Depression Connection

An article in the October issue of Pharmacy Practice News highlighted the common association between Parkinson’s disease (PD) and depression. The story follows up on the sad suicide of Robin Williams, who had struggled with depression for a long time before being diagnosed with PD not long before his death.

I’ve written often about this connection. Depression often accompanies PD; along with constipation and insomnia, it’s a common non-motor symptom of the disease. There is also evidence that depression is associated with later onset of PD. In any case, estimates suggest that half of the one million Americans with PD also deal with depressive symptoms during their lives.

Because the article appeared in a trade group publication, it emphasizes the role pharmacists can play when they interact with their PD patients. Naturally, the PD-depression connection is something all healthcare professionals should keep in mind.

Writing for her fellow pharmacists, Sarah Melton -- associate professor at the Bill Gatton College of Pharmacy, East Tennessee State University (ETSU), in Johnson City, TN -- said: “The most important thing is that you are very conscientious about following up to make sure the medication is working and they’re not having any adverse effects. And you always want to ask about suicidal ideation.”

Those Tough Questions
Melton said that many providers are uncomfortable asking the important questions, like “Have you thought about hurting yourself?” or “Have you ever thought the world would be better off if you weren’t here?”

A depressed person with Parkinson’s should ideally hear those kinds of questions from his primary physician.

Lawrence J. Cohen -- psychiatric pharmacist and professor of pharmacotherapy at the University of North Texas System College of Pharmacy in Fort Worth – said that Robin Williams’ progression from depression to suicide wasn’t unusual:
People get depressed pretty quickly. Patients find out that they have Parkinson’s disease and as part of that, they have the behavioral depression that goes along with realizing that they’re not going to live forever and their movements might get in the way of being able to take care of themselves and be independent. You can imagine how it all starts to snowball.

The possible link between medications – either for PD or depression – and suicide isn’t new. For years, the FDA has required warnings about that link on packaging for antidepressants. In addition, the gold-standard medication for PD -- carbidopa-levodopa -- typically includes a package insert cautioning clinicians to carefully observe their patients for signs of depression and “concomitant suicidal tendencies.”

Chicken or Egg?
Psychiatric pharmacist Talia Puzantian said Williams’ suicide begged the question: “Was it the medication or the underlying disease that caused the suicides? Often, years before any of the symptoms of Parkinson’s disease appear, patients may develop signs of depression.

There’s another consideration, too, according to Puzantian: “Depression in Parkinson’s disease, left untreated, can increase the physical manifestation of Parkinson’s and worsen its progression.”

To date, there is no scientific evidence linking PD meds to depression or suicide. However, increased risk of suicide has been shown in PD patients who undergo deep brain stimulation (DBS), during which surgeons implant electrodes to regulate the brain’s electrical activity in patients for whom the standard meds just haven’t worked.

Dr. Melton urged her colleagues to carefully monitor their patients with PD… patients who typically take a variety of medications. She recommended initiating those “difficult conversations” about depression and suicide, and carefully investigating possibilities of adverse drug interactions with PD meds. Medicines for high blood pressure, antidepressants, antipsychotics, and sedatives are regular culprits.

PD Patients with Psych Disorders: Special Challenge
Dr. Cohen – the psychiatric pharmacist in Fort Worth – explained that managing meds is particularly difficult for PD patients with psychiatric disorders:
It is really complicated, because you’re balancing neurotransmitters in different ways. Most difficult would be a patient who has a psychotic disorder and parkinsonism, because basically you’re kicking up the level of dopamine with Parkinson’s treatments, and you’re bringing down dopamine at the receptor when patients are treated with antipsychotics. So in a way it’s in direct opposition.

Dr. Melton added that cognitive therapies can be as effective for depressed PD patients as medication, a claim we often hear from psychiatrists about the power of talk therapy. She said, “Parkinson’s patients can really benefit if they have a therapist who works with them on depressive symptoms and on changing the way they process the different thoughts they have, especially if they become suicidal.”

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