“Honey, Did You See That Squirrel in the Living Room?”

Visual hallucinations can be a common occurrence in people with Parkinson’s disease. Here’s why and what to do about them.

by Matt McMillen Health Writer

Out of the corner of your eye, you see a small, shadowy form. You know that nothing’s really there, but you can’t deny that you saw something. For the sizable number of people with Parkinson’s disease (PD) who develop hallucinations, this is often the first type of false vision they’ll see.

“The earliest form [are] shadows in the periphery of your vision,” says Barbara Changizi, M.D., a neurologist who specializes in treating movement disorders such as Parkinson’s at Ohio State University’s Wexner Medical Center in Columbus. “That will be the first sign that something is starting to creep up.”

Parkinson’s disease primarily affects your ability to move by damaging the parts of the brain that control motor function. This can cause difficulties with walking, balance, and coordination, as well as tremors and stiffness. But the disease also can have other neurological effects. For an estimated 20% to 40% of people with PD, that includes visual hallucinations.

Hallucinations from PD can range from harmless to deeply upsetting for those who experience them. (And they can be tough on caregivers, too.) But why, and how, do visual mirages manifest from this disorder? And what can be done to treat them?

What’s Happening in the PD Brain

Parkinson’s disease is diagnosed in approximately 60,000 Americans every year, and almost one million people in the U.S. currently live with the disease, according to the Parkinson’s Foundation. It usually develops after age 60, but an estimated 4% are diagnosed with the disease before age 50. Men are 1.5 times more likely than women to develop it. Researchers still don’t know why.

PD usually progresses slowly. In its early stages, you may not have any noticeable symptoms. But as it progresses, often over many years, the disease kills or damages neurons, or nerve cells. The affected neurons are found primarily in a part of the brain called the substantia nigra, which helps control movement of the body. As those neurons go offline, they can no longer produce enough dopamine, a brain chemical called a neurotransmitter that carries necessary instructions for the complex coordination of nerves and muscle cells whenever you move.

It's not entirely understood why Parkinson’s disease triggers visual hallucinations, but some experts speculate that as dopamine production gets disrupted, it has a downstream, hallucination-inducing effect on other neurotransmitters in the brain, such as norepinephrine and acetylcholine.

“Over time, the brain itself becomes more diseased, and the structures that are capable of thinking and producing hallucinations are getting impacted from the disease process,” explains Dr. Changizi.

Which puts them at higher risk of hallucinations, says Brittany LeMonda, Ph.D., a senior neuropsychologist at Lenox Hill Hospital in New York City. “People who are farther along in the disease, who develop dementia or cognitive impairment, are more likely to develop hallucinations,” she adds.

How Hallucinations From PD First Present

Dr. Changizi says that hallucinations may be indistinct at first but usually become progressively more vivid.

“As [neurological damage from PD] progresses the shadows may become more formed,” she explains. “For example, you’ll see a shadow dart across the floor, which will resemble a bug or a mouse.”

In time, the hallucinations likely will begin to seem more real. Seeing small animals such as cats is typical. Or, you may think you see someone in the room with you. Outside your window, it may appear that people are gathering in your yard.

In the earlier stages of the disease, people with PD usually understand that what they are seeing is not real during the fleeting moments that the hallucinations occur. This is officially called “insight.”

“A lot of times people with Parkinson’s have awareness that they’re occurring,” says LeMonda. “They [know] these are hallucinations.”

Reality and False Sightings May Slowly Blur

As their disease progresses, people with PD can lose that insight and the ability to distinguish between hallucinations and reality.

To complicate matters, a frequent cause of visual hallucinations in PD is the medications that are used to treat the motor issues that often come with this disorder. Dopaminergic drugs are mainstay treatments; they work by increasing dopamine levels in the brain and include Sinemet (carbidopa-levodopa), as well as dopamine agonists such as Mirapex (pramipexole) and Requip (ropinirole.) These drugs help dramatically with movement problems, but the boosted dopamine levels the drugs provide cause chemical changes in the brain that may lead to symptoms of psychosis, which include visual hallucinations.

In addition to such false visual sightings, psychosis also may involve delusions, says Dr. Changizi.

“You may think that someone’s trying to kill you, that a family member is in disguise or cheating on you, that the FBI is following you,” she says. Such delusional thoughts are distinct from hallucinations and are less common, she adds.

Harmless or Upsetting, Hallucinations Need Treatment

Visual hallucinations may be benign and non-threatening, such as a furry creature dashing across the rug or a deceased loved one standing nearby. “Sometimes they may have a sense that someone is in the room with them, even if they don’t have a visual hallucination,” says LeMonda of PD patients. “They’ll just get the sense that someone is nearby.”

Fortunately, people with PD rarely have the type of auditory hallucinations typical of schizophrenia, which can cause you to hear voices, Le Monda adds.

Even so, that doesn’t mean you should just ignore them, both experts agree.

Dr. Changizi emphasizes that the experience of hallucinations will vary from person to person. “It’s really individual,” she says. “They can be anything. I’ve had a patient who saw an entire construction crew working on a house outside their home. It was not there.”

She recommends that you call your doctor at the first sign of false visual sightings, including those that are mild and non-threatening. “Even if they are benign, we pretty much always treat [them] because you never know at what point it will cross over to be something scary, and at some point the patient will lose insight that it’s a hallucination,” says Dr. Changizi.

Treatment usually means an adjustment of medication that was prescribed to improve motor functioning. Your doctor may lower your dopaminergic medication to help prevent triggering hallucinations. However, a dose that’s too low won’t offer the needed benefits the drug provides. An alternative to this is to add an antipsychotic medication to help control hallucinations without compromising the dopamine enhancement.

Your doctor may also prescribe Nuplazid (pimavanserin), a selective serotonin inverse agonist (SSIA) that targets certain serotonin receptors. Your doc will also review other medications that you take, including over-the-counter drugs. For example, some OTC allergy medications and sleep aids contain anticholinergics, which can cause symptoms of psychosis.

Getting it right takes a skilled practitioner, says LeMonda. “The dopaminergic system is so tricky. With medication, it really is a balancing act.”

How to Handle Your Own PD Hallucinations

As hallucinations progressively seem more real, it’s likely PD is worsening as well. Make sure your doctor is briefed about any new visual developments.

In addition to medication adjustments, you and your loved ones can take steps at home to limit hallucinations, or to help ride them out while remaining calm.

Avoid dimly lit rooms, advises LeMonda, because such spaces tend to encourage hallucinations. “You want good lighting in the evening, like a good lamp next to the bed, because low light can help increase hallucinations,” she says.

Mentally stimulating activities, including reading, playing Scrabble, or other mind-engaging games, or even just having a conversation about topics that interest you, can help keep your mind occupied and reduce the likelihood of a hallucination happening, LeMonda points out.

Dr. Changizi encourages her patients to stick to a regular schedule in familiar surroundings. “Routine is really good, especially for people in the later stages of Parkinson’s,” she says.

That routine should include going to bed and getting up at the same time each day. If you have trouble sleeping, talk to your doctor. “Hallucinations can be tied to sleep disorders, and so that’s something else your doctor can try to address,” says LeMonda.

It’s also important to maintain your overall good health. In addition to activities that encourage brain health, like reading and engaging socially with other people, make an effort to eat well and exercise regularly to protect your heart health. That in turn protects your brain from scarring that can be caused by high blood pressure, smoking, and diabetes.

People who do that, says Dr. Changizi, tend to have healthier brains in general: “They’re more likely to be robust as their Parkinson’s disease progresses and less likely to have cognitive impairments and psychosis because their brains are better able to handle the neurodegenerative process of Parkinson’s.”

What to Do if You’re a Caregiver

While your loved one with PD still has insight and knows when what they see is a hallucination, it will be easier to address them as they occur. “Hallucinations can be redirected with gentle reaffirmation to buy you some time until there’s a medication adjustment,” says Dr. Changizi.

At this point, it’s not a medical emergency, but you want to alert their doctor to any changes in symptoms.

Things can get harder if your loved one loses touch with reality and no longer understands the hallucination for what it is. But don’t try to convince them that what they’re seeing isn’t really there, which may only agitate them.

“If they start to lose insight into the fact that these are hallucinations, or they have started to develop cognitive impairment, sometimes it may make sense to go along with the hallucination, saying something like, ‘Let me squash that bug or carry that cat out of the room,’” advises LeMonda. “Don’t get into an argument if insight is limited. Caregivers need to be understanding and reassure their loved one that they’re safe.”

Dr. Changizi says it’s not uncommon for hallucinations to be frightening. She mentions a patient of hers who saw a gun-wielding gnome shooting at things inside their house. Another was convinced that snakes were coming out of his skin. What you should do depends on the severity of what’s happening.

“Reorient, reassure, have an air of rationality in more benign cases. But if they are really quite psychotic and agitated and, for example, absolutely convinced that they can’t put their feet on the ground because it’s covered in insects, you have to make an emergency call to the doctor,” says Dr. Changizi. “In really extreme cases, we can bring them to hospital and watch them for a day or two while we stabilize the situation and start medications until they’re safe to go home and be around their family.”

Finally, says Dr. Changizi, try to remain hopeful.

“In the right hands, this is absolutely a manageable condition,” she says. “I see a lot of fear and desperation in patients’ families, who worry that this is it and that they’ll have to put their loved one in a home, but often times we can control the situation with the right medications.”

Matt McMillen
Meet Our Writer
Matt McMillen

Matt McMillen has been a freelance health reporter since 2002. In that time he’s written about everything from acupuncture to the Zika virus. He covers breaking medical news and the latest medical studies, profiles celebrities, and crafts easy to digest overviews of medical conditions. His work has appeared, both online and in print, in The Washington Post, WebMD Magazine, Diabetes Forecast, AARP, and elsewhere.