The Latest Science on Treating Parkinson’s Psychosis
Get the facts about the available treatment options for managing psychosis in Parkinson’s disease.
Managing the motor complications of Parkinson’s disease can already feel like a full-time job, but 20% to 40% of people with Parkinson’s disease also end up experiencing psychosis as a complication of the condition, according to the Parkinson’s Foundation. It can be frightening to feel like you or a loved one with Parkinson’s is losing their grasp on reality. Thankfully, though, there are more options than ever to treat psychosis in Parkinson’s disease.
What Is Psychosis in Parkinson’s?
Parkinson’s disease is a disorder in which dying nerve cells in the brain lead to a lack of dopamine, a neurotransmitter that helps control important functions in the body, according to the National Institutes of Health (NIH). This loss of dopamine is what contributes to the symptoms of Parkinson’s, such as difficulty with walking, balance, and tremors. That said, not all Parkinson’s complications are related to movement—others may be related to your ways of thinking.
Enter psychosis, which is when you experience hallucinations (seeing, hearing, or feeling things that aren’t there) and delusions (false beliefs), explains Jennifer S. Hui, M.D., a neurologist with Keck Medicine of University of Southern California in Los Angeles, CA.
Psychosis symptoms can range from mild to severe, says Dr. Hui. For example, mild hallucinations may manifest as patterned wallpaper that isn’t really there, while more intense symptoms may involve delusions that others are trying to hurt you when they are not.
Understanding Psychosis Causes
While it’s not fully understood why psychosis can develop in people with Parkinson’s disease, in general it is believed to be the result of two potential causes: the disease itself and the medications used to treat it, says Ling Pan, M.D., clinical assistant professor of neurology and neurosurgery at NYU Langone Health in New York City.
“In the majority of cases of psychosis in Parkinson’s, the medications can exacerbate any preexisting or underlying disposition to developing psychosis,” Dr. Pan explains. “The same medications that are very effective at treating the motor complications can actually exacerbate psychosis, especially in higher doses.” Most drugs used to treat Parkinson’s work by increasing dopamine in the brain, which helps reduce motor symptoms like tremors—but it’s possible that dopamine also stimulates areas in the brain that could contribute to psychosis symptoms, per the Michael J. Fox Foundation for Parkinson’s Research.
That said, sometimes people develop psychosis as part of the natural disease course of Parkinson’s even when they haven’t been on medications, Dr. Pan adds. It’s possible that the brain changes in Parkinson’s as a result of those dying nerve cells and lacking dopamine levels, may contribute to the development of psychosis, according to the American Parkinson’s Disease Association.
Latest Psychosis Treatment Options
While treatment may not be needed early on if symptoms are mild, says Dr. Hui, there are treatment options available if you develop more severe or frightening hallucinations or delusions that are getting in the way of daily life. And because medications may sometimes be the cause of psychosis in Parkinson’s, oftentimes adjusting medications if the first step to reducing your psychosis symptoms.
Your doctor will likely first evaluate how much medication you are taking, and potentially reduce the dose. The goal is to reach a “happy medium” where you’re taking enough of a drug to reduce your motor symptoms while also not so much that it leads to psychosis, explains Dr. Pan.
But if your doctor has already made all the adjustments they can to your Parkinson’s medication regimen, there are still other options to help manage psychosis, says Dr. Hui, including prescribing additional drugs to specifically target this symptom.
For a long time, the only real options were antipsychotic drugs: quetiapine (Seroquel) or clozapine (Clozaril). “Seroquel is more generally used in psychosis in the elderly, and it can be very effective,” Dr. Pan says. “Clozapine is a last-resort-type medication that we reserve because it can decrease your white blood cell count and requires a lot of monitoring.”
Treating psychosis in Parkinson’s poses a unique challenge compared with psychosis from other causes, Dr. Pan explains, because many antipsychotics available affect dopamine receptors and can actually make Parkinson’s worse, she says. “That’s why we’re very limited and can’t use other types of antipsychotics that we might use for, for example, schizophrenia-related psychosis.”
Treatment options improved in 2016 with the approval of a brand-new drug called Nuplazid (pimavanserin), according to the Michael J. Fox Foundation. “One option is pimavanserin (Nuplazid) and is specific for psychosis in Parkinson’s,” Dr. Pan says. “It acts selectively on a subclass of serotonin receptors that isn’t used in other dementias, but is very specific to Parkinson’s, and can be effective.”
Because it works by targeting the neurotransmitter serotonin and not dopamine, this drug can help reduce psychosis symptoms without making motor symptoms worse, like other antipsychotics might, says the Michael J. Fox Foundation. Plus, it may also have other benefits, such as improving your sleep quality and decreasing caregiver stress.
Of course, like all medications, there are potential side effects to be aware of: For example, Nuplazid may cause leg swelling, nausea, and confusion, so it’s important to weigh the risks and benefits with your health care team.
The Bottom Line on PD Psychosis Treatments
While managing psychosis in Parkinson’s can be challenging, what with trying to also reduce motor complications like tremors and walking issues, there is hope. Not only can certain antipsychotic medications be effective, but the latest option, Nuplazid, is the first drug of its kind specifically approved for the treatment of psychosis in Parkinson’s. Working with your health care team and caregivers can help you determine the best treatment plan to help reduce distressing psychosis symptoms.
Parkinson’s Information: National Institute of Health. (2017.) “Parkinson’s Disease.” https://www.nia.nih.gov/health/parkinsons-disease
Psychosis in Parkinson’s Information: The Michael J. Fox Foundation for Parkinson’s Research. (2016.) “Ask the MD: Parkinson’s Disease Psychosis.” http://michaeljfox.org/news/ask-md-parkinsons-disease-psychosis
Hallucinations and Delusions in Parkinson’s: Parkinson’s Foundation. (2021.) “Hallucinations/Delusions.” https://www.parkinson.org/Understanding-Parkinsons/Symptoms/Non-Movement-Symptoms/Hallucinations-Delusions
A Guide to Psychosis in Parkinson’s: American Parkinson’s Disease Association. (2021.) “A Guide for Understanding Parkinson’s Disease Psychosis Hallucinations and Delusions.” https://www.apdaparkinson.org/what-is-parkinsons/symptoms/psychosis/