The role of positive and negative interpersonal events on daily fatigue in women with fibromyalgia, rheumatoid arthritis, and osteoarthritis.

Symptoms of fatigue are common to nearly every major chronic illness (Craig et al., 2003; Evans & Wickstrom, 1999; Franck et al., 1999) and are especially prevalent in pain disorders such as Fibromyalgia syndrome (FM), rheumatoid arthritis (RA), and osteoarthritis (OA; e.g., Fishbain et al., 2003; Wolfe, 1999). Wolfe and colleagues (1996) found that clinically significant fatigue was reported by more than 41% of patients with OA or RA, and by 76% of patients with FM. In these conditions, fatigue has been linked with other clinical signs of chronic illness including pain (see Fishbain et al., 2003, p. for a review) and poor sleep (Belza, 1995; Nicassio, Moxham, Schuman, & Gevirtz, 2002; Stone, Broderick, Porter, & Kaell, 1997). In this paper, we take a different approach; we examine predictors of fatigue not directly associated with chronic illness: the everyday occurrence of positive and negative interpersonal experiences. Although most investigators have treated fatigue as a sign of a physical disease process, it is hard to ignore its potential linkages to psychological and social aspects of health and illness. Fatigue or “low energy” continues to be a major criterion for a diagnosis of depression or dysthymia (e.g., , Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, 2000). Moreover, fatigue and depression arise as cofactors not only among those with chronic medical problems, but also healthy individuals (Belza, 1995; Chen, 1986; Kurtze & Svebak, 2001; Lavidor, Weller, & Babkoff, 2002; Nicassio, Moxham, Schuman, & Gevirtz, 2002). Consideration of fatigue as an indicator of affective disturbance as well as poor physical health, invites further exploration of the role of psychosocial factors that have been shown to influence emotional states. The assessment of everyday life events offers a well-established (Zautra, Affleck, Davis, Tennen, & Fasman, 2005)method of examining the ebb and flow of psychosocial stressors and benefits that may influence fatigue. Little is known about relations between fatigue and the everyday interpersonal events, and for those coping with the ongoing demands of chronic pain. Social stressors may further strain the adaptive capacity of pain patients, increasing vulnerability to fatigue (Zautra et al., 2005). Further, fatigue may be thought to arise not only because of the costs of adaptation from chronic stress and depression, but also because of a failure of energy restoration from activities that promote positive well-being (Zautra, 2003). Thus, there may be a unique role of psychosocial deficits in the experience of fatigue over an above the contribution of disease processes. The role of positive social events in experiences of fatigue has not been studied, but from a biopsychosocial perspective (Engle, 1977), we may surmise that such events are likely to increase vitality and decrease fatigue as part of their more general influence in promoting well-being. Positive events have been related to increase in positive affect (Zautra, Affleck, Tennen, Reich, & Davis, 2005). In a prior paper, we found positive affect to be a strong negative association with fatigue (Zautra, Fasman, Parish, & Davis, 2007) With repeated daily records of events and fatigue, it is possible to estimate the influence of both state and trait factors associated with fatigue. Historically, most studies have relied at most on two repeated measures of fatigue, and studied only one illness at a time, a strategy that does not permit examination of differences both between groups and within individuals over time in manifestations of fatigue. Measurement processes capable of repeatedly examining ongoing experiences, such as daily diaries (Bolger, Davis, & Rafaeli, 2003), help correct for recall biases stemming from retrospective reports, and with sufficient observations, can provide a means of obtaining reliable estimates of variance partitioned into two sources: between-persons and within-persons over time (Tennen & Affleck, 1996). Indeed, daily variation in fatigue has not yet been examined in detail, and the findings have the potential to expand the knowledge base regarding psychosocial predictors and properties of fatigue, as well as the extent to which these components vary within and between individuals with different diagnoses. By taking into consideration the established correlates of depression, pain and sleep quality, we first sought to examine the additional influence of both positive and negative daily interpersonal events on fatigue. We then tested whether the relations between daily events and fatigue varied depending on chronic pain condition. Further, we tested whether the event-fatigue relations held true for next day's fatigue to probe the temporal order of these relationships. Finally, we examined whether fatigue itself predicted a health outcome such as diminished physical functioning as a separate analyses exploring outcomes of fatigue. In an effort to probe the reproducibility of the findings to multiple measures, we employed two indicators of fatigue; the primary which is a zero to one hundred rating used in prior studies and as a secondary measures, we included the five item fatigue affect scale taken from the PANAS-X (Watson & Clark, 1994) to see if similar findings would result.