Dr. Richard Isaacson, associate professor of neurology at the University of Miami's Miller School of Medicine, an independent observer of the study said, "This is probably the best in terms of long-term follow study that I've seen in terms of associating dementia with depression." He said prevention and early treatment of depression may be a key saying, "The earlier we diagnose, the earlier we can treat, and, in my clinical experience, the earlier we treat, the better patients will do."
Adam Brickman, assistant professor of neuropsychology at Columbia University Medical Centre, another independent observer emphasised that the study does not say that depression or any other factor causes dementia but a risk factor for dementia. "What this study demonstrates is that depression at a younger age is probably a significant risk factor for dementia," said the director of research of the UK's Alzheimer's Society, Prof Clive Ballard.
Lead author Jane Saczynski, associate professor of medicine at the University of Massachusetts Medical School explained that this study was undertaken because results from association studies of depression and dementia earlier have been confusing and inconsistent mainly because the participants of the study were not followed up for long.
This study followed up participants from the Framingham Heart Study, a large study that has been going on since 1948 to look at heart disease risk factors in Framingham, Massachusetts. Saczynski's team had ready information from the study on heart disease, heart attack, stroke, smoking, alcohol use and other factors that could have influenced dementia. The average age of people that Saczynski's study looked at was 79 years old.
Another theory experts believe to link the two conditions could be that depression is actually a warning flag that comes before dementia. Exercise and social behaviours haven been seen to protect against both depression and dementia Saczynski said. Lifestyle, foods rich in omega-3 fatty acids, controlling cholesterol, abstaining from smoking and, for diabetics, controlling blood sugar are also linked to prevention of both depression and dementia Isaacson explained. Other factors like normal Vitamin E and D levels in blood are also linked to both conditions.
Saczynski said that the team planned to examine the actual link in the brain images and pathophysiology of both depression and dementia.
