Parkinson's disease psychosis: what are neuroleptic drugs?

While exact numbers are not known, estimates suggest up to 40 percent of people with Parkinson’s disease experience psychosis, a condition that causes a person to lose contact with reality.

Psychosis caused by Parkinson’s disease is referred to as Parkinson’s disease (PD) psychosis. The most common symptoms are visual hallucinations, where a person sees something that does not exist. Other types of hallucinations—hearing something that does not exist or sensing a presence—are also common. Delusions (false beliefs) are less common, but also occur.

Treatment for PD psychosis is a multistep process that will vary from person to person. It may involve addressing any underlying causes—like infections, nutritional deficiencies, or coexisting conditions—that are contributing to symptoms. It may involve adjusting the medications a person is taking to treat Parkinson’s disease, which can worsen psychosis symptoms in some cases. If psychosis symptoms are mild and not causing distress, a healthcare provider may recommend no other treatment other than close and careful monitoring.

In other cases, treatment for PD psychosis may involve adding a type of medication called a neuroleptic.

What are neuroleptic medications?

Neuroleptics are a type of medication used to treat psychosis. Also known as antipsychotic medications, neuroleptics are perhaps best known as the main treatment for psychosis associated with severe mental illness, such as schizophrenia.

While there are many neuroleptic medications available, there are only a small number that can be used in the treatment of PD psychosis. Outside of this small number, there are many neuroleptic medications that can make Parkinson’s disease symptoms worse.

Only one of these medications is approved by the U.S. Food & Drug Administration (FDA) for the treatment of PD psychosis. Two others are approved for the treatment of other conditions but have been prescribed off-label to treat PD psychosis.

Off-label prescribing is the practice of prescribing a medication that is approved for one condition to treat a different condition. For example, a healthcare provider may prescribe a neuroleptic drug approved to treat schizophrenia to treat PD psychosis.

Off-label prescribing is common, especially when there are limited treatment options for a condition. This is usually done when there is evidence supporting that the off-label drug can have therapeutic benefit to a person with a specific medical condition, even if the drug is not approved for that medical condition.

How do neuroleptic medications work?

Neuroleptic medications work by changing how the brain uses neurotransmitters, chemicals that enable communication between neurons (nerve cells).

Parkinson’s disease destroys the cells in the brain that produce a neurotransmitter called dopamine. This changes how the brain works, causing problems with movement, balance, and coordination that are the primary symptoms of Parkinson’s disease. These changes are also believed to be the main cause of psychosis symptoms in people who have PD psychosis.

Can neuroleptic drugs cause side effects?

The neuroleptic medications used to treat PD psychosis do come with a risk of side effects. Side effects are an important consideration when deciding on how to treat PD psychosis—and are something that should always be discussed with a healthcare provider.

Here are some questions you can ask when discussing a medication:

• What is the name of the drug being recommended?
• What dosage is being recommended? How often is this medication taken?
• What is the goal of taking this medication?
• What are the potential risks of taking this medication?
• How long will you need to take this medication?
• What side effects can this medication cause?
• Is there a risk of serious side effects?
• Is there a risk of drug or food interactions?
• What will be done to monitor for side effects?
• Is there anything you can do to lower the risk of side effects? Is there anything that you need to avoid doing?
• What should you do if you experience a side effect?

Prepare a list of all medications you take and share it with your healthcare provider. This list should include all medications you are prescribed for all health conditions, as well as any over-the-counter medications, vitamins, nutritional supplements, and herbal supplements. Your pharmacist is also a great source of information.