• Posted November 29, 2023

Brain Inflammation May Trigger Alzheimer's-Linked Anger, Anxiety

Alzheimer's patients are notoriously irritable, agitated and anxious -- and researchers now think they know why.

Brain inflammation appears to influence the mood problems of Alzheimer's patients, rather than traditional markers of the disease like amyloid beta or tau proteins, researchers report in the Nov. 27 issue of the journal JAMA Network Open.

Brain inflammation is strongly associated with caregivers or family reporting rapid mood swings, shifting from calm to agitation or anger, researchers found.

Further, people in higher levels of distress had higher levels of brain inflammation.

This is the first strong evidence that inflammation is a direct cause of the psychiatric and mood symptoms that accompany Alzheimer's, the researchers asserted.

“Neuropsychiatric symptoms such as irritability, agitation, anxiety and depression are among the most difficult symptoms to treat in patients with Alzheimer's,” said lead researcher Dr. Cristiano Aguzzoli, a postdoctoral associate at the University of Pittsburgh School of Medicine. “They are difficult to control, have no clear cause and make it difficult for families to care for their loved one without lots of support.”

“Here, we show for the first time that brain inflammation may be to blame for these symptoms,” Aguzzoli added in a university news release.

The results suggest that treating this inflammation could help ease some of the symptoms of Alzheimer's, the researchers said.

For example, drugs specifically targeting brain inflammation could potentially help reduce some of the anxiety and irritability felt by Alzheimer's patients.

Earlier this year, researchers at the University of Pittsburgh discovered that excessive brain inflammation is critical for Alzheimer's to start, and that it can predict whether an elderly person is at higher risk for Alzheimer's symptoms, according to background notes.

For the study, researchers worked with 109 elderly people, most of whom had no cognitive impairments but had tested positive for amyloid and tau.

Brain scans and clinical assessments of the patients showed that inflammation caused by the brain's immune response was strongly associated with a variety of psychiatric symptoms, including disturbed sleep and agitation.

While amyloid and tau levels could predict these sorts of symptoms, brain inflammation seemed to have an added effect, researchers said.

Symptoms like excess irritability tend to emerge in the early stages of Alzheimer's progression, researchers noted. This could mean that inflammation plays a stronger role in early Alzheimer's than previously thought.

The findings also could also have implications for other degenerative disorders of the brain, researchers said.

“Since both neuroinflammation and neuropsychological abnormalities are found in several other types of dementia, including Parkinson's dementia, we are collaborating with scientists around the world to expand these findings to these other diseases,” said senior researcher Dr. Tharick Pascoal, an associate professor of psychiatry and neurology at the University of Pittsburgh School of Medicine.

More information

Johns Hopkins has more on the psychiatric symptoms of Alzheimer's.

SOURCE: University of Pittsburgh, news release, Nov. 27, 2023