Understanding Parkinson's Disease Psychosis
Medically reviewed by Karen Elta Anderson, MD, Neuropsychiatrist, MedStar Georgetown University Hospital, Washington, DC
Imagine learning to care for a loved one with Parkinson's disease (PD), which is a neurodegenerative brain disorder that affects nearly one million people in the United States. He may move slowly or is rigid, lose his balance easily or shake uncontrollably while resting, which are common symptoms of PD.
But then other symptoms begin to occur. He starts asking why the kids are in the car, but your kids have grown up and moved away. Or he thinks someone is watching him. And, of course, no one is there.
Hallucinations and delusions like these are symptoms of Parkinson's disease psychosis, which occurs in about 50 percent of people with PD at some point during their illness.
Sometimes described as "tricks" played by the brain, hallucinations can cause a person to see, hear, feel, smell or even taste something that isn't real. A person with hallucinations may say they see people or animals that aren't there. As their hallucinations become more frequent, they may not be able to tell what's real and what's imagined and may react to things that aren't real.
Delusions occur less frequently than hallucinations and are generally more difficult to treat. Delusions are fixed, false beliefs not supported by evidence and often have paranoid themes. A common delusion that occurs in people with Parkinson's is that their partner is having an affair, even if they have been married for decades and their spouse is with them nearly all of the time.
When a loved one is experiencing hallucinations and delusions, it can add more frustration to the already challenging physical limitations of Parkinson's. Research has found that hallucinations and delusions can lead to increased distress, greater responsibility for caregivers, and even nursing home placement.
Yet, as difficult and distressing as these hallucinations and delusions may be, only about 10 percent to 20 percent of patients who have hallucinations or delusions associated with PD proactively report the symptoms to their health care providers.
That may be because they don't understand that these symptoms are associated with PD or are embarrassed to report that they are experiencing visions and false beliefs. Sometimes these "invisible" symptoms can cause more problems than the motor issues—especially if people with Parkinson's don't seek help.
Hallucinations and delusions usually appear later in the disease's progression and often catch caregivers by surprise if they and the doctor are focused on motor symptoms, which are easier to identify.
Causes of Parkinson disease psychosis
The cause of hallucinations and delusions associated with Parkinson's is not clearly understood. The drugs commonly used to treat PD, which raise dopamine levels to improve motor control, can cause physical and chemical changes in the brain that may lead to hallucinations and delusions. In addition, the natural progression of Parkinson's disease may cause brain changes that trigger symptoms.
Treatment for Parkinson's disease psychosis
A health care provider can help to identify hallucinations and delusions associated with Parkinson's, monitor signs that symptoms may be progressing, and offer ways to help manage any related challenges.
The first step is for the physician to confirm that the hallucinations and delusions are caused by Parkinson's disease by eliminating other possible causes. Once the diagnosis is made, the health care provider will decide how to treat the symptoms. Treatment may involve adjusting or switching PD medications. Antipsychotic medications also may be used, including an FDA-approved treatment option specifically for hallucinations and delusions associated with Parkinson's disease that may be appropriate for some people.
For more information about Parkinson's disease and its non-motor symptoms, such as hallucinations and delusions, visit .