In the United States, fibromyalgia — once called fibrositis — is the most common cause of widespread chronic pain, meaning it affects many parts of the body.

It’s estimated that up to 4 percent of the population suffers from fibromyalgia. Most are women, and African American women are affected more than Caucasians.

It has been described as a deep pain in muscles and ligaments, with stabbing, shooting, and throbbing sensations, as well as numbness, tingling, and burning.

Pain and stiffness are often worse in the morning, when the weather is cold or humid, after unusual amounts of physical activity or inactivity, and during times of heightened stress.

Depression is common and may precede the onset of the diffuse muscle pains.

Sleep disturbances, debilitating fatigue, mental fog, and sensitivity to touch, sound, and light are other common signs. Even after a long sleep, people with fibromyalgia typically don’t feel refreshed.

The condition affects the central nervous system and amplifies pain and other sensations that are not usually painful. As an example, a massage could be excruciatingly painful.

In addition to widespread pain, exhaustion, mental fog, extreme sensitivity to touch, and sleep problems, people suffering from fibromyalgia may also experience one or more of these symptoms:

• Anxiety

• Depression

• Weight gain

• Dry eyes

• Dry mouth

• Allergies and chemical sensitivities

• Heart palpitations

• Bladder problems

• Pain in the chest or hips

Conventional medical treatment does not offer a cure, but aims to reduce the severity of symptoms with medications including antidepressants, pain relievers, and insomnia drugs — all with significant side effects.