Women are more likely to suffer from fibromyalgia, a chronic condition that causes exhaustion, sleep disturbances and diffuse pain in your muscles, tendons, and ligaments, than men, say experts.

Fibromyalgia patients experience a range of symptoms of varying intensities that increase and decrease over time and often resemble other conditions that often leads to misdiagnosis.

"There are various theories, depending on which research you're looking at, but nothing absolutely definitive has come forward yet," said Elisabeth Deffner, executive editor of Fibromyalgia AWARE, a publication of the National Fibromyalgia Association in Anaheim, Calif.

Doctors must rely on patient histories, self-reported symptoms, a physical examination and an accurate manual tender point examination.

Researchers are examining hormones, immune system differences, brain chemistry and genetics, among other areas, to shed light on the sex differences.

As the causes of fibromyalgia are not clear and no cure exists, the goal of treating fibromyalgia is to control symptoms and minimize discomfort.

"Practitioners must diagnose and treat co-morbidities of fibromyalgia," said Shanda Shribbs, Executive Director of the National Fibromyalgia Research Association in Salem, Ore.

"Untreated restless legs, sleep apnea and upper airway resistance syndrome can have a dramatic impact on sleep and fatigue.

"Other conditions such as cervical cord compression, irritable bowel syndrome and myofascial pain syndrome are frequent co-morbidities which should be considered and treated when they are present," she said.

Common medications for treating fibromyalgia pain include analgesics (including NSAIDs or non-steroidal anti-inflammatory drugs), muscle relaxants and anti-seizure drugs.

Medications to ease sleep disturbances include: anti-depressants and short-term use of sleeping pills.