Many neurological conditions are progressive. The disease begins, perhaps mildly at first, but then gets worse. This is the hallmark of conditions like Parkinson’s, Alzheimer’s and multiple sclerosis.
Depression, however, has not been seen as a progressive disease. New research from the Centre for Addiction and Mental Health (CAMH) shows definite brain changes to patients who have suffered from long-term depression.
The study looked at brain scans of patients who had experienced untreated depression for different periods of time. Dr. Jeff Meyer of CAMH’s Campbell Family Mental Health Research Institute is the senior author on the work that investigated the role of brain inflammation in depressed patients. Dr. Meyer explained, “Greater inflammation in the brain is a common response with degenerative brain diseases as they progress, such as with Alzheimer’s disease and Parkinson´s disease. While depression is not considered a degenerative brain disease, the change in inflammation shows that, for those in whom depression persists, it may be progressive and not a static condition.”
In the study, the patients who had suffered from depression for more than ten years had higher levels of inflammation in the brain than those patients who had been ill for less than ten years. Dr. Meyer and his colleagues at CAMH are particularly knowledgeable in the area of inflammation and depression, having done previous research that revealed for the first time definitive evidence of inflammation in clinical depression.
Inflammation in the study was calculated by using positron emission tomography (PET). In the brain immune cells respond to illness or injury. Too much response creates inflammation similar to what is seen in degenerative brain disease and depression. A protein called the translocator protein (TSPO) is a marker for inflammation and shows up on PET scanning.
The study volunteers were in three groups. Twenty-five patients had been experiencing depression for more than ten years, another 25 for less than ten years and a control group of healthy patients. The TSPO levels of the group that had depression for more than ten years, were about 30% higher than those whose illness had been a shorter duration. The long-term patients also had higher levels than the healthy group.
The results will likely point to more research into medications that target inflammation as options for those with depression. New drugs are in development. However, the team at CAMH believes the research shows that existing medications might be re-purposed for patients with depression. The video has more information on this new avenue of research, check it out.
Sources: CAMH, Lancet Psychiatry,
