The relation between the symbol digit modalities test, fatigue, depression, and anxiety symptoms in a Belgian MS cohort.

A complex relationship exists between cognitive performance, fatigue, and neuropsychiatric symptoms in Belgian people with MS. The level of disability and fatigue adversely affects the cognitive function in MS, whereas depression and anxiety seem to not have a significant effect. A more complex relationship exists between fatigue and neuropsychiatric symptoms, with a divergent interplay between the different dimensions of fatigue that supports the multidimensional approach to assessing fatigue in MS.