Link between high testosterone, aggression in male Alzheimer's patients

Studies have found that having lower testosterone levels increased the risk for developing Alzheimer's disease, said Dr. James Hall, Professor of Psychiatry and Behavioral Health.

"But once someone already has Alzheimer's, higher levels of testosterone are related to acting-out behaviors," he said. "Those behaviors, such as agitation and delusions, occur at some point in at least 70 percent of Alzheimer's patients."

The findings raise concerns about the increasingly common practice of prescribing testosterone-replacement therapy for older men, Dr. Hall said.

"What we're showing is that testosterone can have a negative impact on patients with Alzheimer's disease," he said. "It may be crucial to consider the possible unintended consequences before a patient is placed on testosterone-replacement therapy."

Alzheimer's disease, which is currently irreversible, incurable and fatal, affects 5 million Americans. Researchers at UNT Health Science Center are working to better understand the disease in an effort to find better ways to manage, treat and eventually cure Alzheimer's.

For the study, 87 elderly men with mild to moderate Alzheimer's disease were evaluated. Dr. Hall found the likelihood of having hallucinations was 5.5 times greater for the men with higher levels of testosterone than those with lower levels.

What makes these acting-out behaviors so problematic is they are often especially difficult for caregivers to manage.

"It can be extremely stressful, both physically and psychologically, to care for the person at home," Dr. Hall said. "Acting-out behaviors are the most frequent reason for placement in a nursing home or institutionalized setting."

More studies are needed to verify the link between testosterone and these acting-out behaviors, Dr. Hall said. The hope is that such studies could lead to better ways to identify at-risk patients and thus develop early interventions, he said. Specific treatments to address these behaviors could then be developed.