NEW YORK (Reuters Health) – The results of a study published in the journal Arthritis and Rheumatism suggest that patients with fibromyalgia syndrome, a disorder characterized by chronic pain in the muscles and bones, have a high prevalence of sleep disturbances, which play an important role in exacerbating their symptoms.

Dr. Silvia M. Bigatti, of Indiana University-Purdue University in Indianapolis and colleagues analyzed sleep, pain, depression, and physical functioning in 600 patients with fibromyalgia syndrome. All of the patients completed an assessment at the beginning of the study; 492 were available to complete another assessment 1 year later.

The definition of “problem sleeper” was met by 96 percent of the patients at the beginning of the study and by 94.7 percent 1 year later. The investigators found that none of the patient variables at the beginning of the study predicted quality of sleep.

However, the quality of sleep at the start of the study predicted the degree of pain 1 year later, the extent of pain at the beginning of the study predicted physical functioning 1 year later, and physical functioning at the start of the trial predicted the extent of the patient’s depression after 1 year.

“Past research in fibromyalgia syndrome had found a number of symptoms that are prevalent, including pain, reduced ability to perform everyday tasks, sleep problems, and depression,” Bigatti said in an interview with Reuters Health.

“It has not been clear up to now whether one of these symptoms caused the others, because they are all identified at the same time and they are all related,” she explained. “There are many practitioners (who) believe that it may be depression that causes fibromyalgia symptoms, which impacts how patients are treated in clinics. Our study shows that, in fact, depression is at the end of a cascade of symptoms that begin with sleep problems.”

“Our findings indicate that (this population) may benefit greatly from treatments, both medical and behavioral, geared toward improving sleep,” Bigatti continued.

“Better sleep medications have been developed recently that may help this group particularly,” she said. “Behavioral clinicians can teach these patients good sleep hygiene techniques that may work with the medication to improve sleep.”

The researcher concluded that, “based on our findings, improving sleep will improve pain, functioning, and depression.”

SOURCE: Arthritis and Rheumatism, July 15, 2008.