Could Clinical Depression Cause Alzheimer’s?
Mar 31, 2015 09:54AM ● Published by Jack Etzel
According to the Alzheimer’s Association, figures for both deaths and dollars continue to make it the most expensive and expanding condition in the nation, with the direct costs of caring for those with Alzheimer's totaling an estimated $214 billion in 2014.
A Pittsburgh team is in the forefront of the struggle to decrease or alleviate this disease of the brain, including Meryl A. Butters, Ph.D., associate professor of psychiatry at the University of Pittsburgh School of Medicine and director of the Geriatric Neuropsychology Research Program at the Western Psychiatric Institute and Clinic.
North Hills Monthly Magazine (NHMM): Dr. Butters, can you explain what causes Alzheimer’s in the first place?
Dr. Meryl Butters: No one knows what causes Alzheimer’s disease. We know that there is a long period during which there is a slow build-up of abnormal proteins. Beta-amyloid plaque and neurofibrillary tangles are somehow involved and eventually cause neurons—in other words, brain cells—to start dying. That, in turn, leads to the clinical symptoms of impaired thinking and memory, as well as the behavior changes of dementia.
NHMM: What have you learned from your recent research, most specifically, about depression?
Dr. Butters: We have found that a history of depression seems to increase one’s risk of developing dementia in the future. As you might know, the most common form of dementia is Alzheimer’s disease. At this time we don’t know why this happens; specifically, we don’t understand why a mood disorder that can strike at any age, and that is treatable with antidepressant medications and/or psychotherapy, would increase the risk of developing Alzheimer’s, a disease that is related to plaque and tangle build-up. At this time, we are continuing to study several different things that may go wrong in the brain when people are depressed that could contribute to dementia in later years.
NHMM: What else can you tell us about these studies?
Dr. Butters: We are just now completing two studies; one is a three-year pilot study in which we tried to improve brain health by intervening to prevent depression in people with mild cognitive impairment (MCI), and mild depression, a very common symptom in those with MCI. We are comparing the use of problem-solving therapy, or PST, plus physical exercise in a group of older adults with MCI and depression, against a control group. We used the pilot data to propose to the National Institutes of Health that they should fund a larger study in which we would finally determine whether intervening in mild depression to prevent major depression will help to slow cognitive decline and allow people with progressive decline to maintain their independent functioning longer with a higher quality of life.
NHMM: And the second study?
Dr. Butters: The second study looked at the amount of beta amyloid, one of the bad proteins involved in Alzheimer’s disease and vascular disease, in the brains of depressed people, compared to those who have never been depressed. The results of this study, which took place over a five-year period, are still preliminary, but it appears that the amount of amyloid plaque associated with Alzheimer’s disease was the same—that is, it was not higher in those who had suffered depression. But the number of small strokes in those who had depression and cognitive impairment was greater compared with those who’d never been depressed. We also are about to launch a new, similar five-year study in which we will be seeking people with major clinical depression to undergo brain scans to help us learn more about the relationship between depression and the brain abnormalities that are associated with dementia.
NHMM: It would seem that a person would lessen their chances of dementia by not experiencing clinical depression, but what do we do to avoid or decrease that probability?
Dr. Butters: We do believe that by intervening early when one first starts to experience mild depression, there is a good possibility of preventing it from progressing to full-blown major clinical depression. This means that people should ask for and clinicians should offer treatment for even mild depression. Preventing mild depression from developing into major depression may help protect the brain and promote brain health, and thereby slow decline in cognitive function, in other words, thinking and memory.
NHMM: Are these findings going to somehow change the way that the medical world thinks about or treats these two diseases?
Dr. Butters: We are getting close to figuring out what the links between depression and dementia are. Does depression cause it? We can only say that it can contribute. Once we understand how they are linked, we may be able to develop treatments that target these links in order to reduce the bad brain outcomes that may be associated with major depression.
NHMM: Is there anything on the horizon that might show some hope for treating, postponing or lessening these cognitive declines?
Dr. Butters: With the aging of the baby boomers, agencies that fund research have recently become very interested in finding ways to slow cognitive and functional decline, that is, to extend people’s healthiest years. Researchers are looking into whether we can intervene to change what we call ‘modifiable risk factors’ for cognitive decline. These include things like promoting a healthy diet, especially the Mediterranean diet, increasing physical exercise, engaging in mindfulness meditation and preventing major depression.