Study Determines Link Between Depression and Alzheimer’s Disease

In a recent study published in the International Journal of Geriatric Psychiatry, a team of researchers from the ECU’s Centre of Excellence for Alzheimer’s Research and Care at Edith Cowan University have found a strong association between depressive symptoms and cognitive decline.

In the study titled “A depressive endophenotype of poorer cognition among cognitively healthy community-dwelling adults: results from the Western Australia memory study”, the team of researchers led by Dr. Hamid Sohrabi evaluated the utility of an endophenotype of the depression–cognition link previously shown to be related to cognitive functioning in mild cognitive impairment and Alzheimer’s disease. According to Dr. Sohrabi, the study laid the groundwork to develop a new screening test for cognitive decline caused by psychiatric comorbidities such as depression.

Data was sought from the Western Australian Memory Study with the Cross-national comparisons of the Cambridge Cognitive Examination-revised (CAMCOG-R) scores and 30-item Geriatric Depression Scale (GDS) scores. The researchers assessed these scores to examine the association between the relationship of the five-item depressive endophenotype (DepE) scale drawn from the GDS and the performance level on a measure of cognitive functioning.

“We found that the signs of depression begin well before the symptoms of dementia begin manifesting,” he said. “Our findings confirm there is a core group of symptoms that may enable us to differentiate between people at risk of developing dementia and normally aging individuals. This means we can develop a test that will allow us to differentiate between people at risk of developing dementia and normally ageing individuals.”

Dr. Sohrabi said that therapies for the treatment of depression could be beneficial to slow the cognitive decline in elderly people.

“About half of all incidences of Alzheimer’s disease are associated with genetic risk factors. This research will help us to screen the other half who do not possess these genetic risk factors for dementia including Alzheimer’s disease,” he said. “If we can identify the subset of older adults where depression is a primary factor in cognitive decline they may benefit greatly from therapeutic interventions. This could take the form of antidepressant drugs as well as encouraging lifestyle changes that help combat depression such as exercise, getting enough sleep and social interaction,” he said.