Monday, March 25, 2002
Psychosis with Alzheimer's may run in families By Alison McCook NEW YORK, Mar 25 (Reuters Health) - Many people with Alzheimer's disease also have psychotic symptoms, and a recent study shows Alzheimer's patients whose siblings have both disorders are more likely to exhibit psychosis, as well. "This paper may be the strongest evidence to date that psychotic symptoms in Alzheimer's disease have a distinct biologic basis, with unique genetic underpinnings," said lead author Dr. Robert A. Sweet of the University of Pittsburgh, Pennsylvania. Alzheimer's disease is a type of dementia affecting an estimated 4 million Americans. The symptoms of Alzheimer's disease worsen over time. People may exhibit mild forgetfulness in the early stages of disease, but eventually become unable to care for themselves. Up to 50% of Alzheimer's patients also exhibit psychotic behaviors such as delusions and hallucinations, and psychotic Alzheimer's patients tend to deteriorate more rapidly than patients without psychosis. In the study, published in the March issue of Neurology, Sweet and his colleagues examined data from siblings of 371 people with Alzheimer's. The investigators found that patients with an Alzheimer's disease sibling with psychosis were more than twice as likely to also have psychotic behaviors. These results suggest that there may be a genetic basis to psychosis in Alzheimer's, as well as to the rapid decline associated with psychotic symptoms. In an interview with Reuters Health, Sweet explained that knowing a loved one's hallucinations or delusions may come from his or her genes could help families understand and feel compassion towards such a patient. "The understanding that what the families often see as deliberate disturbing behavior may be as biological as the forgetfulness of Alzheimer's disease may help them respond appropriately to managing these symptoms in their loved ones," he said. Sweet added that further investigations into the genetic basis of psychosis in Alzheimer's disease may help uncover the genes involved in the disease, and could also reveal genes that cause psychotic symptoms in other conditions, such as schizophrenia or Parkinson disease. However, Sweet noted that finding that psychosis in Alzheimer's disease runs in families does not necessarily mean the connection between Alzheimer's and psychosis is genetic. Siblings also share similar environments early in life; they undergo early brain development in the same womb, and often have similar nutritional and educational experiences as children. "Even though these siblings at the time they got Alzheimer's disease were quite old, and likely lived apart many years, one cannot exclude the possibility that these early shared experiences could affect their vulnerability to psychotic symptoms after the Alzheimer's disease starts," Sweet said. Furthermore, Sweet recommended that all families of Alzheimer's disease patients receive counseling on how to deal with hallucinations and delusions in these patients, since almost half will develop psychotic symptoms. "I think that general counseling about what to look for and how to react is important to all families, given how high the rate is in everyone," he said.