The study, lead by Dr. Winfried Hauser, of Klinikum Saarbrucken in Germany, found that fibromyalgia patients had less pain, fatigue and depression while on certain antidepressants.

Tricyclic and tetracyclic antidepressants helped the most to reduce pain, fatigue and sleep disturbances, according to the report published in the Jan. 14 issue of the Journal of the American Medical Association. Serotonin and noradrenaline reuptake inhibitors helped with those three symptoms but to a much lesser extent, while selective serotonin reuptake inhibitors and monoamine oxidase inhibitors helped lessen pain some.

Fibromyalgia affects up to nearly 6 percent of people in North America and Europe, carrying with it high direct and indirect disease-related costs.

"Since evidence for a long-term effect of antidepressants in [fibromyalgia] is still lacking, their effects should be re-evaluated at regular intervals to determine whether benefits outweigh adverse effects," the authors wrote in a news release from the journal. "The identification of patient characteristics associated with positive and negative therapeutic outcomes are needed to better target antidepressant therapy for [fibromyalgia]."

More information

The National Fibromyalgia Association has more about fibromyalgia .