In a study of 109 women with MS, researchers pinpoint an area of the brain with reduced tissue volume, and show that this reduction is linked to high levels of depression, and with a specific type of depression involving mood. The investigators analyzed imaging and clinical data obtained by David Mohr, PhD (Northwestern University, Chicago) in a previous study that tested a stress management program in people with MS (read more about this study
here).
The current study lends important insight to efforts to find solutions for this common symptom of MS. Stefan Gold, PhD (University Hospital Hamburg-Eppendorf, Hamburg, Germany), Nancy Sicotte, MD (University of California, Los Angeles) and colleagues published these findings in
Human Brain Mapping (
2014; 35: 30–37). The study was funded by the National Institutes of Health, the European Union, the Skirball Foundation; and the U.S. Department of Defense. Dr. Sicotte is continuing these studies with funding from the National MS Society.
Background:
Depression is common during the course of multiple sclerosis, but the biological basis for depression in MS is not completely understood. Fatigue is another common symptom experienced by people with MS, and MS fatigue may overlap with the type of fatigue experienced by people who are depressed. In previous studies of people with MS (
Biological Psychiatry 2010;68:553-559), Dr. Sicotte and colleagues found evidence that depression is linked to brain volume loss in the hippocampus, a region deep in the brain known to be important in memory processes and the regulation of mood and emotions. The technique used to detect thickness changes in the hippocampus required a labor-intensive manual analysis of MRI images.
The Study: Dr. Sicotte’s team sought to further understand the potential link between specific regions of the hippocampus with MS-associated depression, and also to tease out how this brain structure relates to different types of depression. A total of 109 women with MS were evaluated, using a clinical scale that measures depression, and MRI scans of the hippocampus. In this study, a computerized imaging technique was used to detect changes in the hippocampus, automating the process and expediting it considerably over previous studies. The method used to measure levels of depression specifically determined whether the depression was “affective” (involving depressed mood and loss of interest), versus fatigue or other motor signs, disrupted sleep or appetite, or interpersonal issues.
The results suggest that women with MS who have high levels of depression showed significantly reduced volumes (thinning and changes in shape) specifically in the right section of the hippocampus. These changes in volume were linked to the type of depression involving mood and loss of interest, and were not associated with fatigue or other typical components of depression.
Because the original telephone counseling study included a much smaller number of men, the present study included only women. Until a similar study is conducted in men with MS, there is no way to know whether a similar relationship would be found in men between volume changes in the brain and depression.
Conclusions: This study yields important information about depression in people with MS. The finding that depression was specifically related to mood suggests that depression in people with MS may not be related to fatigue. The authors note that the new computerized technique greatly facilitated this study, and would be suitable for larger scale studies which need to be conducted to understand the specific associations of hippocampal volume and affective depression in MS. Such studies are necessary to determine the best treatment for MS-related depression.
In an effort to find solutions so that people with MS can live their best lives every day, the National MS Society is funding Dr. Sicotte to continue this research. Her studies could help lay the groundword for the development of therapies that will specifically target major depression in MS.