THE ROLE OF ANXIETY AND DEPRESSION IN FATIGUE AND PATTERNS OF PAIN AMONG SUBGROUPS OF FIBROMYALGIA PATIENTS

This study explored the relationship of anxiety and depression with tw o major symptoms of fibromyalgia, pain and fatigue,among fibromyalgia patients (N = 322). Due to collinearity between anxiety and depression scores, extreme groups were defined according to high versus low anxi ety and depression scores. Two-thirds of the initial sample were exclu ded by this approach, which permitted a two by two factorial split-plo t ANOVA for the assessment of main effects and the interaction of anxi ety and depression upon pain and fatigue. Results stated independent, additive, effects of anxiety and depression upon levels of pain and fa tigue, whereas interaction between anxiety and depression failed to si gnificantly explain symptom differences among the participants. Correl ational analyses indicated widespread pain among the low anxiety subgr oups. In contrast, widespread pain was not indicated among anxious pat ients with low scores on depression. The findings support the hypothes is that (1) anxiety and depression are independently associated with s everity of pain symptoms in fibromyalgia, and that (2) patients with h igh anxiety and low depression may communicate to the medical doctor i n ways that involve a risk of diagnosing fibromyalgia when the criteri on of widespread pain is not supported. These conclusions were confirm ed by results from ANCOVAs that permitted more extensive control of co llinearity among variables.