Evaluation and Treatment of Depression May Help Patients with Mild Cognitive Impairment.

Evaluation and treatment of symptoms of depression may improve or maintain cognitive functioning in some older patients diagnosed with mild cognitive impairment, according to a new study co-authored by a School of Public Health researcher.

The study, published in the Journal of Alzheimer’s Disease, demonstrated that measuring neuropsychiatric symptoms such as depression, anxiety, agitation, and irritability helps to predict who will progress from normal cognition (NC) to Mild Cognitive Impairment (MCI), and then who will either progress from MCI to Alzheimer’s disease (AD) dementia or revert back to NC.

“Although further research is needed, these results will help design better clinical trial studies for Alzheimer’s disease in the future,” says Yorghos Tripodis, research associate professor of biostatistics.

MCI is a state in between normal cognition and Alzheimer’s disease (AD) dementia, in which the individual has a subjective complaint of memory and other cognitive difficulties and performance on formal neuropsychological testing is abnormal for age, but these problems do not interfere with routine independent functioning. The majority of people with MCI have progressive memory and cognitive impairment, and eventually are unable to function independently with daily tasks, resulting in a diagnosis of dementia. However, some individuals with MCI do not get progressively worse and some people improve, reverting back from MCI to normal cognition.

The researchers analyzed data from 6,763 individuals participating in research studies at 34 Alzheimer’s Disease Centers across the US that are currently or were previously funded by the National Institute on Aging. The participants, whose average age was 72, received annual neurologic examinations and evaluations of their memory and cognitive functioning as well as their neuropsychiatric symptoms. Partners (e.g. significant others) also rated participants’ neuropsychiatric symptoms and level of functioning. Participants were diagnosed at each evaluation as either cognitively normal, MCI, or AD dementia by teams of doctors. All participants in this study were cognitively normal at the time of their first examination and were then followed from 2 to 12 years, with an average of 5 years.

Of the participants, 1,121 converted from NC to MCI; of those, 324 reverted back to NC and 242 progressed to AD dementia. The results showed that individuals with normal cognition were more likely to progress to MCI if they had more depression, anxiety, or other mood symptoms. Similarly, people who had progressed to MCI were more likely to progress even further to AD dementia if they had more of these neuropsychiatric symptoms. Approximately one-third of the participants who had progressed to MCI reverted back to normal cognition, and the participants who reverted back had significantly lower neuropsychiatric symptoms and a greater reduction in depression symptoms. In particular, the researchers noted that improvements in depression and mood symptoms led to a greater likelihood of cognitive improvement.

“The implication is that successfully identifying and providing effective treatment for these neuropsychiatric symptoms, including depression, may potentially improve or maintain cognitive functioning in many older adults,” says lead author Robert Stern, professor of neurology, neurosurgery, and anatomy & neurobiology at the School of Medicine, and clinical core director of the Alzheimer’s Disease Center.

But Stern cautions, “There are many possible explanations for these findings, and further research is needed to address this important issue.”

Co-authors from the Alzheimer’s Disease Center included Michael Sugarman, Michael Alosco, and Eric Steinberg.