Psychosis in Parkinson's disease: An LTC perspective
Joseph Friedman, M.D.
The single most important precipitant for placement of Parkinson's disease patients in a long-term care facility is psychiatric dysfunction, particularly psychosis. Although PD is classified as a movement disorder and clinically diagnosed purely based on movement disorder criteria, non-motor, neurological and psychiatric features are crucially important, particularly as the disease progresses.
Commonly detected non-motor symptoms associated with PD include depression, found in 30-50% of patients (depending on the criteria used) and dementia, which did not used to be considered an important feature, but develops by the time of death in about 80% of patients. Anxiety affects about 40%, fatigue affects about 50% (without any correlation with motor severity), apathy affects about 50% (usually associated with dementia) and psychotic symptoms occur in about 30% of patients taking medication for their PD.
Psychotic symptoms may surprise many healthcare professionals, and there is a need to understand how they present in the PD patient, particularly since the symptoms are very different than those that occur in schizophrenia and other primary psychiatric disorders. Visual hallucinations are the most common feature, and are almost always without emotional content. The images are usually people but often animals. They tend to occur in low stimulation environments, when the patient is alone reading or watching TV. He or she may see children playing in the living room or workers planting shrubs in the yard. The images are silent and usually don't pay any attention to the patient. In the beginning, the patient may talk to the hallucination and when it ignores him, the patient goes to the hallucination only to have it disappear.
Patients will sometimes enjoy the hallucination or find them baffling. A patient told me that he had seen a tractor outside his hospital window, and that this was bizarre since he was on the third floor. Another told me that he enjoyed his hallucination. It was of a baby. He saw it every night and, he noted with a smile, “it never made any noise.” Auditory hallucinations are about half as common as visual, with tactile, olfactory and a sensation of taste considerably less common. The hallucinations may look real, or appear in black and white, or even look like cartoons. They may appear for a few seconds or may be present all the time. They tend to be the same each episode.
The hallucinations sometimes feel threatening. When a patient awakens at night and sees a strange man, it is difficult to not be frightened. The hallucinations may become real to the patient so that he puts out food for the guests, or argues with his wife about calling the police. Available at the Parkinson's Disease Foundation website is a video of brief descriptions by PD patients of their hallucinations.
Delusions, another symptom of Parkinson's disease psychosis (PDP), can often be more problematic than hallucinations. A hallucination is a false sensory stimulus, whereas a delusion is a false and irrational belief, which often causes paranoia in the patient. The most common delusion is of the spouse having an affair. This often becomes the “straw that broke the camel's back” in precipitating nursing home or long-term care placement. Other common delusions include the family is abandoning the patient, people are stealing or spying, or people living in the house who don't belong there.
Treatment is, like everything else in PD, individualized. It is important to eliminate contributing factors such as infections, particularly bladder and lung, and other medication effects. Probably the most common medication contributors are anticholinergics used for overactive bladder. When medical problems and other psychoactive medications are excluded, then PD medications are reduced. PD experts recommend that anticholinergics, like trihexiphenidyl and benztropine, be tapered and stopped first, then amantadine, then dopamine agonists, MAO-b inhibitors and COMT inhibitors, and L-Dopa last of all.
When taking this approach, there is a dilemma in that one cannot usually reduce the PD medications much without imposing worsening mobility. There is no drug approved specifically to treat PDP, so when this point is reached, anti-psychotic agents are introduced. To date, there are only two “second-generation” anti-psychotic drugs that have been studied and identified as controlling for psychosis without worsening motor function in PD: clozapine (at doses between 6.25 mg and 50 mg at bedtime) and quetiapine. Regarding the latter, open label studies show it is effective without affecting motor function, but blind, randomized trials do not. All other antipsychotics have been reported to worsen motor function in PD patients.
An alternative approach to treating PDP is to use cholinergic enhancers, the drugs used to treat Alzheimer's dementia. These have less support for their use and can take several weeks to work. A new drug in development for PDP, pimavanserin, targets serotonin receptors that play a role in psychosis and does not affect dopamine. In clinical studies, pimavanserin was found to be a safe and effective treatment for PDP that does not compromise motor function. If approved by the FDA, this may provide a new and much-needed treatment option for PDP. In the meantime, it is important to understand how the condition presents in PD patients so that an individualized management plan can be developed.
Joseph H. Friedman, M.D., is a Stanley Aronson Professor of Neurodegenerative Disorders and Director at the Movement Disorders Program of Butler Hospital. He also is a professor and Chief, Division of Movement Disorders at the Alpert Medical School of Brown University.