Parkinson's Disease: A Guide to Mind and Mood

How Parkinson's can change a person's mood, thinking, and behavior
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Quick summary

Some of  the most profound consequences of Parkinson's disease may result not from motor symptoms, but from psychiatric and behavioral difficulties. These problems often go unrecognized and untreated. Here's what to watch for.

Changes in mood, thinking, and behavior

Many family caregivers don't realize that some of the most stressful challenges of Parkinson's can come from changes in a patient's mood, thinking, and behavior. For instance, depression, dementia, and drug-induced psychosis are potentially crippling conditions that often accompany Parkinson's. Yet doctors and researchers haven't paid much attention to such troubles.

"If the patients do mention it" -- and, typically, they don't -- "it kind of gets shoved to the side by the issues that are more interesting to the doctor rather than to the patient," says neurologist Joseph Friedman, director of the Parkinson's Disease and Movement Disorders Center at NeuroHealth in Warwick, Rhode Island, and author of Making the Connection Between Brain and Behavior: Coping with Parkinson's Disease .

Not every Parkinson's patient experiences the problems listed below, but if you notice any of them in the person you're caring for, tell his neurologist or nurse. Some of the difficulties can be relieved by adjusting Parkinson's drug dosages or giving other standard treatments. Be sure to ask about potential side effects, some of which may worsen certain Parkinson's symptoms.

Depression and anxiety

Sad or hopeless feelings

About 40 to 50 percent of people with Parkinson's develop depression. Usually it's mild to moderate in intensity, but roughly 5 to 10 percent of cases are the more severe form known as major depression. Evidence suggests that depression results partly from neurochemical changes in the brain caused by the Parkinson's disease process -- it's not just a psychological reaction to having the illness.

Diagnosing depression in a person with Parkinson's disease can be complicated, because the two disorders share many symptoms: fatigue, loss of pleasure or interest in normal activities, problems with sleep, slowness of movement, lack of facial animation. Parkinson's patients may look sad even when they're not, because on top of having stiff facial muscles, they speak softly and don't respond quickly.

To correctly identify the mood disorder, doctors look for distinguishing clues such as sustained feelings of sadness, worthlessness, guilt, or irritability. Depression can be treated with psychotherapy and drugs, such as selective serotonin reuptake inhibitor (SSRI) drugs or tricyclic antidepressants. In severe cases, electroconvulsive therapy may be considered.


About 40 percent of Parkinson's disease patients struggle with anxiety, often in tandem with depression. So-called generalized anxiety makes individuals so worried and edgy that they can't sleep or they experience a racing heartbeat, shortness of breath, and sweating. Such symptoms can be provoked by distress and embarrassment over how others may react to seeing their Parkinson's tremor or shuffling gait, and the problem can hurt their ability to perform at work or enjoy social gatherings. Even worse, anxiety itself can aggravate Parkinson's motor symptoms.

People with Parkinson's also often suffer anxiety when their levodopa or dopamine agonist drugs start wearing off. They fear that the next dose won't control their symptoms again, or that they'll be stranded out in public, unable to move well. Extreme anxiety can produce scary panic attacks that leave the patient unable to breathe and feeling as if he's having a heart attack. For some, social situations provoke such an intense bout of nerves that they develop a social phobia and shun any gatherings.

Anxiety disorders can be allayed with SSRI antidepressants or antianxiety drugs such as Valium.

Fatigue and dementia

Feeling tired, unmotivated, or less sharp

About half of people with Parkinson's disease complain of fatigue. Some feel sleepy, whereas others report low energy or an exhaustion that levels them. Doctors will explore to what extent the symptoms result from depression or sleep problems; addressing those disorders may relieve the fatigue. Exercise may also help, so Friedman encourages patients to slowly work up to a regular walking routine of 30 minutes a day. If fatigue still persists, he sometimes prescribes stimulants.

As Parkinson's disease becomes an ever-greater obstacle to everyday routines, roughly 40 percent of patients exhibit apathy. They lose interest and joy in the hobbies or activities that used to bring them pleasure, and they seem indifferent to the friends, family, and events around them. They stop caring about anything.This can be upsetting to see in a patient, especially because it seems as if he's giving up on treatment and on life. Then again, apathy may protect him from distress and frustration over his growing disability, Friedman points out. Apathy may be related to depression, dementia, or sleep disorders, so addressing those conditions may help. Generally, however, there's no good cure for apathy.

Most people with Parkinson's disease will at some point experience mild cognitive changes that may hinder attention, memory, mental processing speed, problem-solving, processing of visual information, and the ability to pull the right words from one's vocabulary. In many cases, patients compensate for these subtle deficits without much detriment to life at work or home.

Showing signs of dementia

Severe impairment of memory and thinking, along with confusion and disorie ntation, may develop with dementia, the worst of the nonmotor Parkinson's symptoms. It can render the patient incapable of taking on daily activities of living. Although research studies vary widely on the numbers, experts generally estimate that 30 percent of Parkinson's patients suffer from dementia.

Usually, dementia arises in later stages of Parkinson's. If major cognitive trouble arises early, another illness is likely to blame, such as Alzheimer's disease or a Parkinson-like disorder called dementia with Lewy bodies (which actually looks similar to very late-stage Parkinson's dementia).

The dementia of Parkinson's disease is somewhat different from that of Alzheimer's, although there are similarities, says Friedman. Alzheimer's patients don't record new memories and wouldn't remember a grocery list of five items. People with Parkinson's dementia would store the memory of the items but may not recall them until you give hints or cues. Patients struggle more with language and forgetting of words and names in Alzheimer's than in Parkinson's. On the other hand, Parkinson's dementia patients are, earlier on, "very bad at judging spatial relationships between objects, which can be a problem with their driving," Friedman says. "They have trouble organizing, they have trouble multitasking."

The Alzheimer's drug Exelon (rivastigmine) was federally approved for treating dementia in Parkinson's in 2006, but its benefits are relatively modest, says Friedman. The same appears true of other Alzheimer's drugs in the same category, called cholinesterase inhibitors.

Sees things that aren't there or experiences paranoia

Hallucinations and paranoia

Hallucinations are a side effect in about 30 percent of people taking Parkinson's drugs -- particularly dopamine agonists -- and they usually occur only after many years. The problem is more likely to arise in patients with dementia. A symptom of psychosis, the hallucinations are often benign at first, involving visions of children, strangers, or animals around the home. Usually, a Parkinson's patient realizes the episodes aren't real but may not tell anybody about them for fear that he's losing his mind.

Parkinson's drugs may also trigger serious psychosis, in which people can't tell what's real and what's not. About 5 to 10 percent of people with Parkinson's disease get caught up in delusions (false or illogical beliefs) and paranoia -- such as becoming convinced that others are spying on them. The most common delusion, says Friedman, is that the patient's spouse is having an extramarital affair. Such distressing psychotic symptoms can make the patient extremely difficult to care for, and they're a major factor leading to placements in nursing homes.

To treat hallucinations and delusions, doctors switch or try to reduce the Parkinson's medicine -- but the catch-22 is that the pills are crucial for controlling the patient's motor problems. Physicians may prescribe atypical antipsychotic drugs such as Seroquel (quetiapine) or Clozaril (clozapine).

Sleep problems

It's common for people with Parkinson's disease to complain of excessive drowsiness during the day. Several factors are to blame. One is that, for various reasons, most Parkinson's patients don't get enough sleep at night. When levodopa or dopamine agonists wear off in the nighttime, symptoms of stiffness, tremor, and slowness of movement resurface, says Kelly Lyons, a research associate professor of neurology at the University of Kansas Medical Center in Kansas City. A severe tremor might wake the person, as might stiffness as he tries turning over in bed. Or discomfort may keep him from falling asleep to begin with.

Another complication is that Parkinson's patients tend to suffer from sleep disorders, including:

* Sleep apnea -- interrupted breathing episodes during slumber
* Periodic limb movements -- repeated jerking motions of the legs while asleep
* Restless leg syndrome -- uncomfortable tingling or crawling sensations in the legs, causing an irresistible urge to move them during sleep
* REM sleep behavior disorder -- "acting out" of vivid dreams, sometimes leading to punching or kicking of bed partners

What's more, studies show that Parkinson's drugs have sedative effects, says Lyons. The challenge is to try adjusting the medication dose or scheduling, or switching to another drug, while still keeping motor symptoms well controlled. Other medicines prescribed for anxiety, depression, and psychosis can also cause daytime sleepiness. Altogether, Lyons says, "the whole sleep cycle is just really messed up" for the Parkinson's patient.

Compulsive behavior

Secret gambling or other compulsive behavior

Use of Parkinson's drugs, particularly dopamine agonists such as Mirapex (pramipexole), has on occasion led to uncontrollable gambling, shopping, or preoccupations with sex, or to obsessive repetition of certain activitie s such as collecting or counting particular objects. Reducing or changing medication may resolve the problem.

For more information online:

Download Parkinson Disease: Mind, Mood, and Memory, a comprehensive brochure from the National Parkinson Foundation's free publications page.

Search for information on depression and anxiety at the National Institute of Mental Health's publications page .

Check out the Parkinson's Disease Foundation's fact sheet, "Coping With Dementia: Advice for Caregivers" .

Ingfei Chen

Ingfei Chen has witnessed the hope and hype and miracles and failings of medical care and scientific research during more than 15 years of covering both areas as a journalist. See full bio