Hallucinations and delusions are potential complications of Parkinson’s disease (PD). They may be severe enough to be classified as PD psychosis.

Hallucinations are perceptions that aren’t really there. Delusions are beliefs that aren’t based in reality. One example is paranoia that persists even when a person is presented with contrary evidence.

Hallucinations during PD can be frightening and debilitating.

There are many factors that can contribute to hallucinations in people with PD. But the majority of cases occur as side effects of PD medications.

Hallucinations and delusions in people with PD are often part of PD psychosis.

Psychosis is fairly common in people with PD, especially those in later stages of the disease. Researchers estimate it occurs in up to 50 percent of people with PD.

Studies show that symptoms of psychosis are related to elevated activity of a brain chemical called dopamine. This often occurs as a result of medications that are used to treat PD.

However, the reason why some people with PD experience psychosis while others don’t isn’t quite understood yet.

Most hallucinations with PD are fleeting and not usually harmful. They can become frightening or bothersome, though, especially if they occur frequently.

Hallucinations can be:

  • seen (visual)
  • heard (auditory)
  • smelled (olfactory)
  • felt (tactile)
  • tasted (gustatory)

Delusions affect only about 8 percent of people living with PD. Delusions can be more complex than hallucinations. They may be more difficult to treat.

Delusions often start as confusion that develops into clear ideas that aren’t based on reality. Examples of the types of delusions people with PD experience include:

  • Jealousy or possessiveness. The person believes someone in their life is being unfaithful or disloyal.
  • Persecutory. They believe that someone is out to get them or harm them in some way.
  • Somatic. They believe they have an injury or other medical problem.
  • Guilt. The person with PD has feelings of guilt not based in real behaviors or actions.
  • Mixed delusions. They experience multiple types of delusions.

Paranoia, jealousy, and persecution are the most commonly reported delusions. They can pose a safety risk to caregivers and to the person with PD themselves.

PD isn’t fatal, though complications from the disease can contribute to a shorter expected life span.

Dementia and other psychosis symptoms like hallucinations and delusions do contribute to increased hospitalizations and increased rates of death.

One study from 2010 found that people with PD who experienced delusions, hallucinations, or other psychosis symptoms were about 50 percent more likely to die early than those without these symptoms.

But early prevention of the development of psychosis symptoms may help increase life expectancy in people with PD.

Your doctor may first reduce or change the PD medication you’re taking to see whether that reduces psychosis symptoms. This is about finding a balance.

People with PD may need higher doses of dopamine medication to help manage motor symptoms. But dopamine activity shouldn’t be increased so much that it results in hallucinations and delusions. Your doctor will work with you to find that balance.

Medications to help treat Parkinson’s disease psychosis

Your doctor might consider prescribing an antipsychotic drug if reducing your PD medication doesn’t help manage this side effect.

Antipsychotic drugs should be used with extreme caution in people with PD. They may cause serious side effects and can even make hallucinations and delusions worse.

Common antipsychotic drugs like olanzapine (Zyprexa) might improve hallucinations, but they often result in worsening PD motor symptoms.

Clozapine (Clozaril) and quetiapine (Seroquel) are two other antipsychotic drugs that doctors often prescribe at low doses to treat PD psychosis. However, there are concerns about their safety and effectiveness.

In 2016, the Food and Drug Administration (FDA) approved the first medication specifically for use in PD psychosis: pimavanserin (NuPlazid).

In clinical studies, pimavanserin was shown to decrease the frequency and severity of hallucinations and delusions without worsening the primary motor symptoms of PD.

The medication shouldn’t be used in people with dementia-related psychosis due to an increased risk of death.

Psychosis symptoms caused by delirium may improve once the underlying condition is treated.

There are several reasons someone with PD might experience delusions or hallucinations.


People with PD often have to take several medications. These medications help treat the PD and other conditions associated with aging. However, these medications can have many side effects.

Taking medications that affect dopamine receptors is a significant risk factor. This is because some PD medications increase dopamine activity. High activity of dopamine can lead to hallucinations and emotional symptoms in people with PD.

Medications that may contribute to hallucinations or delusions in people with PD include:

  • amantadine (Symmetrel)
  • anti-seizure medications
  • anticholinergics, such as trihexyphenidyl (Artane) and benztropine
    mesylate (Cogentin)
  • carbidopa/levodopa (Sinemet)
  • COMT inhibitors, such as entacapone (Comtan) and tolcapone (Tasmar)
  • dopamine agonists, including rotigotine (NeuPro), pramipexole
    (Mirapex), ropinirole (Requip), pergolide (Permax), and bromocriptine
  • MAO-B inhibitors, such as selegiline (Eldepryl, Carbex) and rasagiline (Azilect)
  • narcotics containing codeine or morphine
  • NSAIDs, like ibuprofen (Motrin IB, Advil)
  • sedatives
  • steroids


Chemical and physical changes in the brain can contribute to hallucinations and delusions. This is often seen in cases of dementia with Lewy bodies. Lewy bodies are abnormal deposits of a protein called alpha-synuclein.

This protein builds up in areas of the brain that control:

  • behavior
  • cognition
  • movement

One symptom of the condition is having complex and detailed visual hallucinations.


A change in a person’s concentration or awareness causes delirium. There are many situations that can trigger a temporary episode of delirium.

People with PD are sensitive to these changes. They can include:

  • a change in environment or an unfamiliar location
  • infections
  • electrolyte imbalances
  • fever
  • vitamin deficiencies
  • a fall or head injury
  • pain
  • dehydration
  • hearing impairment


Depression among people with PD is quite common. Researchers estimate at least 50 percent of people with PD will experience depression. The trauma of a PD diagnosis can take a toll on a person’s mental and emotional health.

People with major depression can also have symptoms of psychosis, including hallucinations. This is called psychotic depression.

People with PD who have depression may misuse alcohol or other substances. This could also trigger episodes of psychosis.

Antidepressants can be used to treat depression in people with PD. The most commonly used antidepressants in PD are selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine (Prozac).

Arguing with someone experiencing hallucinations or delusions is rarely helpful. The best you can do is to try to remain calm and acknowledge the person’s thoughts.

The goal is to reduce their stress and keep them from becoming panicked.

Psychosis is a serious condition. It may lead a person to harm themselves or others. Most hallucinations in people with PD are visual. They’re not usually life threatening.

Another way to help is to take notes on the person’s symptoms, such as what they were doing before the hallucinations or delusions started, and what kinds of perceptions they claimed to experience. Then you can share this information with them and their doctor.

People with PD psychosis tend to remain silent about experiences like this, but it’s essential that their treatment team understands the full range of their symptoms.

It’s important to know that experiencing hallucinations or delusions caused by PD doesn’t mean that a person has a psychiatric illness.

Most of the time, PD psychosis is a side effect of certain PD medications.

Speak to your doctor if you or someone you’re caring for is experiencing hallucinations.

If psychosis symptoms don’t improve with a change in medication, your doctor may prescribe an antipsychotic medication.