In order to investigate the associations between fatigue and depression, disability, and disease subtype, 207 individuals with clinically definite Multiple Sclerosis (MS) were administered the Fatigue Severity Scale and the Zung Self-rating Depression Scale during a regular clinic appointment. Their current level of disability was established using the Expanded Disability Status Scale. Fatigue and depression were highly correlated (r=0.58), even when the depression measure was corrected for items overlapping with fatigue and other symptoms or consequences of MS (r=0.44). Fatigue and disability were also correlated (r=0.33). Multiple regression revealed that both depressed mood and disability were significant predictors of fatigue, together accounting for approximately 23% of the variance in patients' self-reported fatigue. The combined groups of primary progressive (n=45) and secondary progressive patients (n=25) appeared to have higher fatigue scores than relapsing-remitting patients (n=137). However, an analysis of covariance revealed that this apparent difference was in fact attributable almost exclusively to differences in disability among the three subtypes of MS. Other reports of differences in fatigue between subtypes of MS should be re-examined in light of this finding.

The relationship between disability and depression was studied in 188 patients with clinically definite multiple sclerosis (MS). Patients were administered the Zung Self-Rating Depression Scale, Ways of Coping, Uncertainty of Illness Scale, and Hope Scale during their regular clinic appointments. Their current level of disability was rated by the attending physician using the Expanded Disability Status Scale. Even when the depression measure was corrected for items overlapping with other symptoms or consequences of MS, depression was correlated with disability. Depression was also correlated with an array of psychological variables, including uncertainty concerning ones illness, hope, and the use of various emotion-centered, though not problem-centered coping strategies. Multiple regression analyses revealed that none of these psychological correlates mediated or moderated the relationship between disability and depression. Instead, disability, uncertainty, hope, and emotion-centered coping were significant independent predictors of depression, together accounting for approximately 40% of the variance in patients' self-reported depression. The relationship between disability and depression in MS is usually interpreted as evidence that depression is psychogenic and reactive to the demands and limitations of this disease. The demonstration that this relationship is not diminished when an array of potentially intervening psychological variables are included in the analysis raises questions concerning the validity of this interpretation.

Individuals with multiple sclerosis were asked to identify stressors they had experienced over a 6-month period and the coping mechanisms employed to deal with those stressors. Subjects who reported currently experiencing an exacerbation of symptoms were compared with those in remission or in the chronic phase of their illness. Of the 61 subjects who completed the Hassles Scale, Uplifts Scale, and Ways of Coping, those classified as being in an exacerbation phase of MS were found to have significantly higher hassles scores than those in the chronic phase. A significant difference was also found in terms of a factor labeled 'passive avoidant and aggressive coping' derived through a factor analysis of the Ways of Coping subscales. Subjects in the exacerbation subgroup had higher scores on this coping factor than those in the chronic subgroup. The difference in hassles scores remained significant after between-group differences in length of illness and reported number of symptoms were controlled through an analysis of covariance, although the difference in coping fell short of significance in this covariance analysis.

The following correlates of depression were examined in a sample of 166 patients with clinically definite relapsing-remitting (n=140) or secondary progressive (n=26) multiple sclerosis: (a) the present state of the patients' illness (i.e., whether or not they were currently experiencing an exacerbation of their symptoms); (b) their level of uncertainty concerning their illness; and (c) their strategies for coping with their illness. A current exacerbation in symptoms, greater uncertainty of illness, and greater use of emotion-centered forms of coping were all related to depression. Multivariate analyses revealed that uncertainty of illness played a pivotal role as a mediating variable. Exacerbations in illness appeared to heighten patients' levels of uncertainty, and it was largely through this heightened uncertainty that the increases in depression came about.