Journal of the International Neuropsychological Society (2010), 16, 1039–1046. Copyright © INS. Published by Cambridge University Press, 2010. doi:10.1017/S1355617710000834 1039 INTRODUCTION Depression is more common in multiple sclerosis (MS) than in many other chronic diseases, with most lifetime prevalence estimates around 50% (Patten & Metz, 1997; Sadovnick et al., 1996). However, after decades of research, it remains unclear what combination of factors is most important in pre- dicting depression, as the consideration of disease factors such as lesion burden, brain atrophy, functional disability, fatigue, and cognitive dysfunction leave a substantial amount of variance unexplained. A recent model developed by Arnett, Barwick, and Beeney (2008) proposes that stress, social support, and other factors may moderate the effect of disease factors on depression in MS. However, few studies have been conducted investigating the roles of these potential moderators. Stress has consistently been shown to be positively asso- ciated with depression in MS and effect sizes are typically moderate to large (Aikens, Fischer, Namey, & Rudick, 1997; Arnett et al., 2008; Devins et al., 1996; Gilchrist & Creed, 1994; Kneebone & Dunmore, 2004; McCabew & De Judicibus, 2005; Pakenham, 1999; Patten et al., 2000; Ron & Logsdail, 1989). While many of these studies have looked at timing and frequency of momentous negative life events, it has been shown that daily events, and how an individual evaluates these events, are more predictive of mental and physical health (Kanner et al., 1981; Lazarus & Folkman, 1984). Fur- thermore, everyday events and chronic daily stress have been found to increase the risk of MS exacerbations and the development of brain lesions more than acute stress (Mohr, Goodkin, Bacchetti, Boudewyn, Huang, Marrietta, et al., 2000). The Hassles and Uplifts Scale is one common way of measuring an individual’s evaluation of everyday stressors and positive experiences, as well as recent, more significant life events (Kanner, Coyne, Schaefer, & Lazarus, 1981). In the current study, the terms uplifts and positive experiences will be used interchangeably. Studies using this and similar scales have shown that has- sles and uplifts might be part of two separate systems, in- stead of representing extremes of the same continuum (Maybery, Jones-Ellis, Neale, & Arentz, 2006). For example, uplifts tend to affect only positive mood and hassles only negative mood (Maybery, 2003, 2004). Therefore, the bal- ance between hassles and uplifts appears to provide the most Positive everyday experiences interact with social support to predict depression in multiple sclerosis GRAY A. VARGAS and PETER A. ARNETT Psychology Department, Penn State University, University Park, Pennsylvania (Received January 13, 2010; Final Revision June 22, 2010; Accepted June 22, 2010) Abstract Both social support and stress predict depression in multiple sclerosis (MS) patients. Little work has been done on the relationship between positive life experiences and depression in this group. Ninety MS patients completed the Social Support Questionnaire (SSQ), the Hassles and Uplifts Scale (HUS), the Chicago Multiscale Depression Inventory (CMDI), and the Affective Reading Span Task (ARST). The Expanded Disability Status Scale (EDSS) was also used. Separate regression analyses were conducted with the EDSS entered at step 1, ARST memory bias score at step 2, SSQ at step 3, either Hassles or Uplifts at step 4, and the interaction term at step 5 to predict depression. Uplifts interacted significantly with social support to predict depression, but hassles did not. After considering disability level, memory bias, and social support and uplifts main effects, the interaction of uplifts and social support accounted for nearly 5% independent variance in depression ( p < .05). These results suggest that the absence of uplifts, combined with low levels of social support, is related to depression in MS patients. More generally, these data indicate that it is important to study the absence of positive experiences along with stress and negative experiences in this population. ( JINS, 2010, 16, 1039–1046.) Keywords: Multiple Sclerosis, Depression, Social support, Uplifts, Stress, Affective bias Correspondence and reprint requests to: Gray A. Vargas, Department of Psychology, The Pennsylvania State University, 420 Moore Building, University Park, PA 16802-3106. E-mail: gav111@psu.edu