Predictive Bidirectional Relations Between Pain, Fatigue, and Dyscognition in Fibromyalgia.

Fibromyalgia (FM) is a common and disabling disorder characterized by chronic widespread pain, fatigue, and dyscognition. Previous studies have shown strong positive correlations between pain, fatigue, and dyscognition. However, bidirectional relationships, particularly with dyscognition modeled as a predictor, have rarely been established. The purpose of this study was to examine the bidirectional, predictive nature of the relationships between these FM symptoms. Pain, fatigue, and dyscognition were measured via the Brief Pain Inventory, Multidimensional Fatigue Inventory, and Multiple Ability Self-Report Questionnaire at baseline and a 2-year follow-up in a large sample of 450 well-characterized female patients with FM. Relationships between FM symptoms were evaluated using a cross-lagged, longitudinal model. Dyscognition, pain, and fatigue were positively correlated at both baseline and follow-up (s .13 -.53, s<.01). Dyscognition at baseline was predictive of dyscognition (=.76, β=.75, <.001), pain, (=.01, β=.09, =.033) and fatigue (=.05, β=.08, =.050) at follow-up. Pain at baseline was predictive of pain (=.59, β=.59, <.001), dyscognition (=.88, β=.07, =.022), and fatigue (=.85, β=.11, =.004) at follow-up. Fatigue at baseline was only associated with fatigue (=.61, β=.60, <.001) at follow-up. Dyscognition is predictive of future pain and fatigue in patients with FM. Continued work should examine dyscognition as a clinical predictor of future severity of core symptoms such as pain and fatigue.