Parkinson’s Treatment Tips on Psychosis and Hallucinations

These are quick tips to work on with your doctor in case of acute worrisome hallucinations and psychosis in the setting of Parkinson’s disease:

  1. Check for a urinary tract infection or pneumonia
  2. Consider the medication list and consider that medications may be the underlying cause, or contributing to the cause especially pain medications, muscle relaxants, and benzodiazepines (valium, ativan, clonazepam)
  3. Consider under the guidance of your doctor a temporary reduction in Parkinson’s treatment medications
  4. In some severe cases experts may consider temporarily stopping anticholinergics (trihexyphenidyl, artane, beztropine, benadryl), amantadine, MAO-B inhibitors (selegiline, rasagiline, zelapar, others), entacapone, and even dopamine agonists
  5. In some severe case small doses of sinemet or madopar are used to try to gain control of the hallucinations/psychosis, but one must be aware this strategy could worsen Parkinson’s disease symptoms
  6. Experts will frequently use dopamine blocking medications such as seroquel or clozaril, but almost never will use other dopamine blockers such as haldol, resperidal, and olanzapine– which all may worsen Parkinson’s symptoms.
  7. Call your neurologist immediately if you experience hallucinations or psychosis.

How commonly do Parkinson’s disease patients develop psychosis?

Psychosis in Parkinson’s disease generally comes in two forms: hallucinations (when patients see or hear or feel things that aren’t really there) or delusions (which are fixed false beliefs). When hallucinations occur, they are mostly visual  (usually these are non-threatening, and patients mostly see small people or animals, or  loved ones who have already died, not interacting with them but doing their own thing) (Zahodne and Fernandez 2008a; Zahodne and Fernandez 2008b; Fernandez 2008; Fernandez et al 2008; Friedman and Fernandez 2000). Sometimes, they can be threatening, but this is less common. Auditory hallucinations (more commonly seen in schizophrenia) are rare in Parkinson’s disease and if they do occur, they are usually accompanied by visual hallucinations.

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.

Unfortunately, psychosis occurs in up to 40% of Parkinson’s disease patients (Fenelon et al 2000). In the early stage of Parkinson’s disease psychosis, the patient often still has a clear understanding and retains their insight, but this tends to worsen over time and insight may eventually be lost. At later stages, 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.

What triggers psychosis in Parkinson’s disease?

Psychosis in Parkinson’s disease is believed to be due to long term use of parkinsonian medications especially dopaminergic and anticholinergic drugs (Fenelon 2008; Zahodne and Fernandez 2008a; Zahodne and Fernandez 2008b; Fernandez 2008; Fernandez et al 2008; Friedman and Fernandez 2000). However, significant medication exposure is no longer a pre-requisite in Parkinson’s disease psychosis (Ravina, Marder, Fernandez, et al 2007). The “continuum hypothesis” states that medication-induced psychiatric symptoms in Parkinson’s disease starts with sleep disturbances accompanied by vivid dreams, and then develops into hallucinations and delusions, and ends in delirium. However this theory is now being challenged (Goetz 1998).

How is psychosis managed?

The urgency of treatment will depend on the type and characteristics of psychosis. Sometimes, when the hallucinations are mild and benign, and insight is retained, it is best that the Parkinson regimen be kept as is. However, when a patient is experiencing more threatening paranoid delusions, then more aggressive treatment is warranted (Zahodne and Fernandez 2008a; Zahodne and Fernandez 2008b; Fernandez 2008; Fernandez et al 2008; Friedman and Fernandez 2000).

The management of psychosis includes:

  1. Ruling out the possible reversible causes (such as infections, metabolic and electrolyte imbalances, sleep disorders)
  2. Decreasing or discontinuing adjunctive antiparkinsonian drugs (with cautious monitoring of motor function). Typically, when a patient is on several anti-parkinsonian medications, we “peel off” one drug at a time, until the psychosis resolves or further ‘peeling’ is no longer practical because of worsening of Parkinson motor symptoms. We usually eliminate drugs in the following order: anticholinergic drugs , amantadine, selegiline or rasagiline, dopamine agonists, catechol O-methyltransferase (COMT) inhibitors, and finally levodopa
  3. Simplifying the Parkinson’s disease medication regimen
  4. Adding a new or second generation antipsychotic (be careful: some antipsychotics can be harmful to Parkinson’s disease patients!)
  5. If psychosis occurs in a Parkinson’s disease patient with cognitive impairment or dementia, a cholinesterase inhibitor (such donepezil, rivastigmine) may be considered

About the Author


Michael Okun

Professor of Neurology, expert on Parkinson's disease and other basal ganglia disorders, deep brain stimulation, author of over 300 research papers and the bestselling book…

Read all articles by Michael Okun