We examined between and within-person variability, affective correlates, and diagnostic differences in daily fatigue in women with rheumatoid arthritis (RA), osteoarthritis (OA), and fibromyalgia syndrome (FMS). Two hundred and fifty-five female patients recruited from the community served as participants for this project. The patients had a physician-confirmed diagnosis of RA (n=89), OA (n=76), or FMS (n=90). Individuals completed an initial questionnaire and up to 32 daily diaries assessing illness symptoms and psychosocial variables (i.e., fatigue, pain, sleep problems, depression, and affect). The primary outcome for the current project was variability in fatigue. We examined affective, pain, and sleep correlates of fatigue, and tested whether these relations varied by diagnosis. Results indicated that FMS patients had higher overall levels of and greater daily variability in fatigue compared with the other pain groups. For all patients, fatigue correlated highly with lower positive affect (PA). Moreover, day-to-day increases in fatigue were associated with decreases in PA, particularly among FMS patients, and with increases in negative affect (NA). Daily pain was associated with increased fatigue in all groups, although OA patients showed less pain reactivity than either FMS or RA patients. These findings indicate that fatigue is a common feature of rheumatologic conditions. Nonetheless, there are important differences between RA, OA, and FM patients in both the everyday manifestations and the biopsychosocial correlates of fatigue.

Despite the predominance of literature focusing on psychologic disturbance in FMS, these analyses identified dysfunctional positive affect regulation as a key feature of FMS. FMS status was uniquely characterized by lower levels of positive affect, especially during stressful weeks. These findings challenge current conceptualizations of FMS and point to new directions for interventions that focus on improving positive affective resources, especially during times of stress.

This study examined whether breathing rate affected self-reported pain and emotion following thermal pain stimuli in women with fibromyalgia syndrome (FM: n=27) or age-matched healthy control women (HC: n=25). FM and HC were exposed to low and moderate thermal pain pulses during paced breathing at their normal rate and one-half their normal rate. Thermal pain pulses were presented in four blocks of four trials. Each block included exposure to both mild and moderate pain trials, and periods of both normal and slow paced breathing. Pain intensity and unpleasantness were recorded immediately following each pain trial, and positive and negative affect were assessed at the end of each block of trials. Compared to normal breathing, slow breathing reduced ratings of pain intensity and unpleasantness, particularly for moderately versus mildly painful thermal stimuli. The effects of slow breathing on pain ratings were less reliable for FM patients than for HCs. Slow versus normal breathing decreased negative affect ratings following thermal pain pulses for both groups, and increased positive affect reports, but only for healthy controls with high trait negative affect. Participants who reported higher levels of trait positive affect prior to the experiment showed greater decreases in negative affect as a result of slow versus normal breathing. These experimental findings provide support for prior reports on the benefits of yogic breathing and mindful Zen meditation for pain and depressed affect. However, chronic pain patients may require more guidance to obtain therapeutic benefit from reduced breathing rates.