To the Editor.
—I read with interest but no surprise the report by Schiffer and Babigian1 of an association between multiple sclerosis (MS) and depression. The authors mention as possible links between the two conditions areas of demyelination within the limbic system, shared genetic vulnerabilities, and selective alterations of monoamine metabolism within the central nervous system. Since depression is also associated with immunerelated disorders such as cancer, infection, and allergy, the possibility of an immunologic factor in the etiology of depression has been raised.2 There is now more direct evidence of immune dysfunction both in MS3 and depression.4 It is therefore possible that, in addition to the factors noted by the authors, immunologic abnormalities may also be involved in both conditions. One such factor may be the ratio of helper/suppressor T lymphocytes, which has been reported to be increased in certain patients with active MS3
Kronfol Z. Multiple Sclerosis and Depression. Arch Neurol. 1985;42(4):310. doi:10.1001/archneur.1985.04060040016004