Long-term consumption of caffeine would worsen the neuropsychiatric symptoms of people with Alzheimer’s disease, according to a study on mice, published in Frontiers in Pharmacology.
So far, many studies have advocated for the consumption of coffee and therefore caffeine to prevent dementia symptoms, both in patients with Alzheimer’s disease and in normal aging processes. However, these new studies suggest that once the cognitive and neuropsychiatric symptoms of the disease have been developed, consuming caffeine would aggravate them.
Alzheimer’s disease is a neurodegenerative disease that leads to the gradual and irreversible loss of mental functions, especially memory. The majority of people affected also have neuropsychiatric symptoms such as dementia, anxiety, apathy, depression, hallucinations or paranoia. Although these symptoms manifest themselves differently in different patients, they are often a source of distress for patients, but also for their relatives and caregivers.
These are precisely the symptoms that interested the researchers. They performed their tests on aged mice, some of which had disorders similar to those of Alzheimer’s disease. “Mice develop Alzheimer’s disease very similarly to that of human patients with an early form of the disease, with not only typical cognitive problems, but also a number of symptoms similar to the behavioral and psychological symptoms of dementia, which makes them a valuable model to check whether the benefits of caffeine will be able to offset its possible negative effects,” says Prof. Raquel Baeta-Corral, lead author of the study.
The researchers subjected the mice to a long oral treatment with a very low dose of caffeine (0.3 mg / mL), the equivalent of three cups of coffee for a human. The results they obtained indicate that caffeine modifies the behavior of healthy mice and aggravates the neuropsychiatric symptoms of those affected by Alzheimer’s disease. The latter thus seem particularly prone to neophobia, the fear of all that is new. They also exhibit anxiety-related behaviors, exacerbating their behavioral and psychological symptoms of dementia. Learning and memory do not seem to have benefited from the effects of caffeine.
“Our observations of the adverse effects of caffeine in a model of Alzheimer’s disease as well as in previous clinical observations, suggest that an exacerbation of BPSD-like symptoms may partially interfere with the beneficial cognitive effects of caffeine,” explains Lydia Giménez-Llort, researcher in the Department of Psychiatry and Forensic Medicine of INc-UAB and principal researcher of the project.