Depression in multiple sclerosis: reactive or endogenous?

Multiple sclerosis is associated with high rates of depression. The extent to which this is related to living with chronic illness or part of the disease process remains unclear. This question was investigated by comparing rates of depression in MS with those in rheumatoid arthritis, which involves similar physical and psychosocial stressors but without central nervous system involvement. The study involved an on-line survey, which included measures of depression not confounded by somatic symptoms, medication use, self-reported physical functioning, pain, and other demographic variables. Results indicated that disease group (multiple sclerosis, rheumatoid arthritis) independently predicted depression above and beyond demographic and disease-related variables. Results support the hypothesis that depression in MS is partly determined by direct neurological consequences of the condition.