Mood and Memory
Back in 2006, a group us that included Drs. Amarilis Acevedo, Elizabeth Crocco, David Loewenstein, Vineeth John, and myself published an article that presented results of a type of study called a meta-analysis. In that kind of study, researchers try to find all available studies on a subject and then combine the data from them. The advantage of this kind of study is that helps us understand results from conflicting studies and may allow us to correct for how well or poorly studies were done.
The subject of our study was whether there is a relation between having a history of depression and getting Alzheimer’s disease later in life. We looked at data from more than 100,00 people who had had depression. Our study, published in the Archives of General Psychiatry, 2006, 63, 530-538, showed that the odds of getting Alzheimer’s were about two times greater in people who had depression as much long as 10-15 years before. A study in the April 8th edition of the journal Neurology confirms this relation (Geerlings et al., Neurology, 70, 1258-1264).
A lingering controversy is whether depression is a risk for Alzheimer’s or whether it is simply an early symptom of it. In a well-known study, one group of researchers reported that people whose memory got better after being treated for depression still got Alzheimer’s later. Some people have argued that being depressed was one of the first sign that they were getting Alzheimer’s.
Other people have suggested that depression, even much earlier in life, may be part of the same process that results in Alzheimer’s disease.
Many researchers today speculate that the process in the brain that results in developing Alzheimer’s disease begins years and even decades before someone has the disease. Researchers are also interested in the connection between cardiovascular disease and Alzheimer’s disease. It turns out that some of the same risks that are related to cardiovascular disease and Alzheimer’s disease are also related to depression. For example, when some people have magnetic resonance imaging (MRI) scans of the brain, something called “white matter changes” are sometimes seen. Many people believe these are caused by vascular disease in the brain, and they are related to having depression.
What does this mean for your brain fitness? I think it shows the importance of keeping cardiovascular risks low, not just to keep your heart healthy but also to keep your brain healthy. If you don’t know about your blood cholesterol level (and associated lipids such as HDL, LDL, and triglycerides), find out. A simple blood test will let your doctor find out more about how your body is taking care of certain substances in your blood. You may want to ask your doctor about another simple blood test for a substance called C-reactive protein. C-reactive protein is a separate marker for cardiovascular risk. If your cholesterol or one of the other lipids needs treatment, your doctor may prescribe diet changes, increased exercise, and a medication from a group of drugs called statins. These medications can improve your lipid profile. People who take statins have reduced risk for Alzheimer’s disease.
