The relationship between depressive symptoms and cognitive dysfunction in multiple sclerosis.
INTRODUCTION: Although it has been well established that otherwise healthy persons with depression experience various neuropsychological deficits, such a relationship has not been robustly supported in the initial investigations using the multiple sclerosis (MS) population. The relative inability to discover a significant relationship between depression and cognitive dysfunction may be due to methodological difficulties in previous studies (e.g., use of correlational analysis; use of neuropsychological measures that are generally not affected by depression). METHODS: The present study examined a control group and 17 MS subjects who reported relatively low (BDI h 9) or high (BDI S 16) depression levels on a variety of neurocognitive measures that were (i.e., PASAT, Digit Span Backward subtest of the WAIS-R, and a modified version of the Buschke Selective Reminding Test; SRT) or were not (i.e., Similarities, Vocabulary, and Digit Span Forward subtests of the WAIS-R) hypothesised to be associated with depression symptomatology. RESULTS: These results support our hypotheses that depressed individuals with MS evidence greater neuropsychological dysfunction relative to their nondepressed counterparts. CONCLUSION: Findings are discussed in terms of the specific cognitive impairments evidenced by depressed subjects with MS. This research may have significant implications with regard to the expected effects of antidepressant and cognitive therapies on neuropsychological functioning in MS.