What You Need to Know About Psychosis in Parkinson’s Disease
Psychosis doesn’t just affect individuals with psychiatric disorders such as schizophrenia. It also affects other illnesses, including Parkinson’s disease (PD), a degenerative disorder that disturbs movement and balance.
Over five million people worldwide have PD, struggling with symptoms such as shaking, stiffness, slowness of movement and instability.
“Psychosis in Parkinson’s disease is very common,” according to Michael S. Okun, M.D., national medical director at the National Parkinson Foundation and author of the Amazon no. 1 bestseller Parkinson’s Treatment: 10 Secrets to a Happier Life.
In fact, psychosis may affect 1 in 5 Parkinson’s patients, he said. And as many as 2 out of 3 patients may experience minor symptoms, “such as non-bothersome visual illusions.” (An example is “seeing something in the corner of your eye that may not be there, [such as] a bug in the sink for an instant.”)
“Patients primarily experience visual hallucinations,” said James Beck, Ph.D, the director of research programs at Parkinson’s Disease Foundation. A smaller number of patients — 10 to 20 percent — experience auditory hallucinations, he said.
Some patients also may experience delusions, or fixed false beliefs. According to Dr. Okun in his piece on managing psychosis in PD:
“Delusions are usually of a common theme, typically of spousal infidelity. Other themes are often paranoid in nature (such as thinking that people are out to steal from one’s belongings, or to harm or place poison on their food, or substitute their Parkinson medications, etc.) Because they are paranoid in nature, they can be more threatening and more immediate action is often necessary, compared to visual hallucinations (Zahodne and Fernandez 2008a; Zahodne and Fernandez 2008b; Fernandez 2008; Fernandez et al. 2008; Friedman and Fernandez 2000). It is not uncommon that patients actually call 9-1-1 or the police to report a burglary or a plot to hurt them.”
In the early stages of psychosis, patients tend to have insight into their symptoms, Beck said. In other words, they realize that what they’re seeing (or hearing) isn’t actually there. But this may worsen over time. According to Okun in the same piece:
“At later stages [of psychosis], patients may be confused and have impaired reality testing; that is, they are unable to distinguish personal, subjective experiences from the reality of the external world. Psychosis in Parkinson’s disease patients frequently occurs initially in the evening, then later on spills into the rest of the day.”
Psychosis typically doesn’t develop until several years after a person has been diagnosed with PD, Beck said.