Psychological symptoms in primary fibromyalgia syndrome: relationship to pain, life stress, and sleep disturbance.

Twenty-five subjects with primary fibromyalgia syndrome and 22 subjects with rheumatoid arthritis were compared on measures of psychological distress, pain, health status, life stress, sleep disturbance, and coping strategies. Higher levels of psychological distress were found in the primary fibromyalgia syndrome group, but the degree of life stress was shown to be a significant covariate.