A team funded by the National MS Society found evidence that depression is linked to brain volume loss in specific subregions of an area of the brain called the “hippocampus,” which is known to be important in memory. Tissue loss in this area was linked as well with abnormal secretion patterns of the stress-related hormone cortisol. The results warrant further study to determine any cause-effect relationship, but are an important clue to a symptom that can interfere greatly with the quality of life of people with MS. The results also hint that this shrinkage may be reversible with effective treatment of depression in MS. Stefan M. Gold, PhD, Nancy Sicotte, MD (University of California, Los Angeles) and colleagues report their findings in Biological Psychiatry(Corrected proof, available online June 19, 2010.
Dr. Sicotte is funded with a research grant from the Society and Dr. Gold was completing a postdoctoral fellowship during the study, which was also funded by the NIH and other sources.
Background: Depression is common during the course of multiple sclerosis. In fact, studies have suggested that clinical depression, the severest form of depression, is more frequent among people with MS than it is in the general population or in persons with other chronic, disabling conditions. In previous studies of people with MS, Dr. Sicotte and colleagues found evidence of tissue loss (also known as atrophy) in the hippocampus, a region deep in the brain known to be important in memory processes. (Brain 2008;131:1134-41). Her team continues to study this area of the brain using high-resolution MRI (magnetic resonance imaging). In this study, they looked for a correlation between brain atrophy in the hippocampus and MS-related depression.
The Study: The team used high-resolution MRI to examine the four subregions of the hippocampus in 29 people with relapsing-remitting MS, and 20 controls without MS. Levels of cortisol, a hormone released in response to stress, were obtained three times daily over two consecutive days. Participants also completed the Beck Depression Inventory, a questionnaire used to assess depression.
The results show that overall, people with MS had smaller tissue volume in the hippocampus than people without MS, particularly in two subregions, but their cortisol levels were not significantly higher. People with MS who were considered to have depression, based on their Beck Depression Inventory scores, had smaller tissue volumes in a third subregion as well, and higher levels of nighttime cortisol than people with MS who were not depressed and also compared to people with MS whose depression was considered to be well controlled with antidepressants.
Comment: This study presents an important clue to the source of some of the depression experienced by people with MS. The authors note that further studies are necessary to determine any cause-effect relationship between cortisol levels and brain tissue volume loss, which are commonly found together in people with severe depression who do not have MS. If the UCLA team’s findings are confirmed, it may lead to future therapies that specifically target this cause of depression in people with MS. Several potentially “neuroprotective” therapies are being tested in people with MS which could also be effective in preventing depression in MS.
Importantly, depression may also be “reactive”—the result of difficult life situations or stresses. In addition, people with MS are also subject to the same forms of depression that affect the general population. Read more about depression in MS and how to cope with this symptom – regardless of its source – to minimize its interference in daily life.