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Use of Antipsychotic Drugs Is Common for Parkinsonís Despite Risks

Physicians routinely prescribe antipsychotic drugs to elderly people with Parkinson’s disease (PD) and psychosis, many of whom also have dementia, according to a study published in the July 2011 issue of Archives of Neurology. This practice continues even though the drugs can worsen Parkinson’s symptoms such as stiffness and tremor, and despite warnings that newer antipsychotic medications increase the risk of death in older people with dementia.

In the late stage of the disease, people with Parkinson’s can develop psychosis — periods of losing contact with reality. At any one time, between 20 to 40 percent of people with Parkinson’s may be experiencing psychosis. Psychosis in Parkinson’s can be mild, e.g., individuals report mistaking objects with animals, but it may progress at times to severe delusions, paranoia and hallucinations. Dementia, meaning difficulties with reasoning or memory such that people cannot care for themselves, may affect up to 80 percent of people with Parkinson’s.

The authors of the new study, led by Daniel Weintraub, M.D., at the University of Pennsylvania, set out to answer two basic questions: How often do doctors prescribe antipsychotic medications to people with Parkinson’s? And did doctors alter their prescribing behavior after 2005, the year the US Food and Drug Administration (FDA) issued warnings about the risks of second generation or atypical antipsychotics?

The researchers analyzed medical records from the Department of Veterans Affairs of about 2,600 people with Parkinson’s and psychosis to find out how many had been prescribed antipsychotics in the year 2008, and which medications they took; some 800 people in this group also had dementia. The scientists compared this to antipsychotics prescribed the same year to a group of about 6,900 people who had dementia but not Parkinson’s. Nearly all were men. Finally, the study authors compared rates of prescription of antipsychotics in 2002 and 2008.


  • In 2008 half of the people with both Parkinson’s and a diagnosis of psychosis, with or without dementia, were prescribed an antipsychotic drug.
  • The most frequently prescribed antipsychotic drug was quetiapine (Seroquel®).Almost 30 percent of people prescribed an antipsychotic drug received so-called high potency antipsychotics, drugs with limited efficacy that are known to exacerbate Parkinson’s motor symptoms.
  • Clozapine, the only antipsychotic drug shown to be effective in people with Parkinson’s, accounted for less than two percent of prescriptions.
  • Prescriptions for “atypical” antipsychotics — newer drugs with less impact on motor symptoms — remained steady between 2002 and 2008, despite a warning about the safety of these drugs for elderly people with dementia.
  • Between 2002 and 2008 doctors shifted from prescribing risperidone and olanzapine to quetiapine and aripiprazole.

What Does it Mean?
Psychosis may be very debilitating to people affected by Parkinson’s and their family members. While there has been significant progress in treating these symptoms in people with psychiatric disorders, e.g., schizophrenia, there is an urgent need for better treatment of these symptoms in Parkinson’s.

Most of antipsychotic medications block dopamine, hence worsening the motor symptoms of Parkinson’s, and many have been shown to shorten life span of those affected by dementia. However, psychosis symptoms can be so overwhelming that treatment would be required. Currently, physicians can either lower antiparkinsonian medications, or start an antipsychotic medication. The authors conclude that physicians need to be better educated about the efficacy of antipsychotic drugs for people with Parkinson’s, their side effects, and their risks. While quetiapine (Seroquel) is often used in clinical practice, as shown in this study (likely because it does not block dopamine receptors in lower doses) the drug has failed to show significant benefit in clinical trials. Clozapine, the only clinical proven efficacious antipsychotic, is likely rarely used because of the administrative burden in prescribing it as well as its own, rare risk of adverse events. In sum, there is an urgent need of new therapies for psychosis in the Parkinson’s community.

Reference: Daniel Weintraub; Peijun Chen; Rosalinda V. Ignacio; Eugenia Mamikonyan; Helen C. Kales. Patterns and Trends in Antipsychotic Prescribing for Parkinson Disease Psychosis.  Arch Neurol. 2011;68(7):899-904.


Source Date: Jul 07 2011