Treating Psychosis in Parkinson’s Disease

One medication can partly tame the scary symptoms of Parkinson’s disease that often come from taking traditional medication: hallucinations, or psychosis.

For years, patients with Parkinson’s disease have faced a tragic choice — taking medicine that may cause hallucinations or medication that may aggravate their tremors.

Parkinson’s disease psychosis

When we think of psychosis, we think of schizophrenia. But of all people diagnosed with Parkinson’s — some one million Americans — about half become out of touch with reality in certain ways, a condition known as Parkinson’s disease psychosis, or PDP.

Most often Parkinson’s disease psychosis comes after patients have had the condition for a while, showing up as mild visual hallucinations. For example, you might see a long-dead cat curled up on your living room sofa.

Sometimes the hallucinations can be scary. A smaller group of patients develop paranoid delusions. One of the most common delusions is that your spouse — typically your primary caregiver — is having an affair. Imagine spooning food into the mouth of a spouse who flies into rages over every unexpected phone call.

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Parkinson's disease typically arrives after the age of 60, when brain cells that produce dopamine become impaired or die. Dopamine helps transmit signals between the parts of the brain that govern movement. As the disease progresses, most people develop tremors that make it hard to do ordinary actions, and they may have difficulty chewing, swallowing, or speaking.

Treating psychosis in Parkinson's

Parkinson’s medications boost dopamine.

That boost may, however, trigger psychosis. On the other hand, drugs for psychosis tend to block the dopamine system, making Parkinson’s worse. As a result, doctors might dial back a Parkinson’s medication or try using various antipsychotics.

It generally takes months before doctors learn about symptoms of Parkinson’s disease, since patients may not realize they’re having psychotic symptoms. Often, until something goes wrong, family members don’t see a danger. By the time the symptoms are severe, the burden often pushes caregivers beyond what they can do. PDP is the main reason people with Parkinson’s end up in nursing homes, some research shows.

One medication could help them remain at home. Pimavanserin, under the brand name Nuplazid, is used specifically for PDF. Rather than affecting a patient’s dopamine receptors, the medication targets the pathways for serotonin, a function of antidepressants.

Nuplazid was designated as a breakthrough therapy and granted priority review status, two programs to speed approval of drugs that could be significantly better than any alternatives. The FDA reached its conclusion based on a six-week clinical trial of 199 participants, showing that Nuplazid could cut the frequency or severity of hallucinations and delusions without affecting motor symptoms.

As reported in The Lancet, taking Nuplazid led to a 37 percent improvement on a nine-point clinical scale, compared to a 14 percent bump for those taking placebo. Other research suggests the medication is the most affect one for treating psychosis symptoms.

Side effects of Nuplazid

There is a downside. The FDA noted that for every two patients who are expected to achieve “much improved” status with Nuplazid, one patient would have a bothersome side effect, which might include confusion. Just over 8 percent of people taking Nuplazid develop severe problems, which include irregular heart rhythms, muscle injury, and weight loss. The FDA, however, has concluded the benefits of the drug outweigh its risks.

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