Fibromyalgia (FM) is a medical condition characterised by chronic widespread pain and a heightened pain response to pressure. Other symptoms include tiredness to a degree that normal activities are affected, sleep problems and troubles with memory. Some people also report restless legs syndrome, bowel or bladder problems, numbness and tingling and sensitivity to noise, lights or temperature. Fibromyalgia is frequently associated with depression, anxiety and posttraumatic stress disorder. Other types of chronic pain are also frequently present.The cause of fibromyalgia is unknown; however, it is believed to involve a combination of genetic and environmental factors, with each playing a substantial role. The condition runs in families, and many genes are believed to be involved. Environmental factors may include psychological stress, trauma and certain infections. The pain appears to result from processes in the central nervous system, and the condition is referred to as a "central sensitization syndrome". Fibromyalgia is recognized as a disorder by the US National Institutes of Health and the American College of Rheumatology. There is no specific diagnostic test. Diagnosis involves first ruling out other potential causes and verifying that a set number of symptoms are present.The treatment of fibromyalgia can be difficult. Recommendations often include getting enough sleep, exercising regularly and eating a healthy diet. Cognitive behavioral therapy (CBT) may also be helpful. The medications duloxetine, milnacipran or pregabalin may be used. Use of opioid pain medication is controversial, with some stating their use is poorly supported by evidence and others saying that weak opioids may be reasonable if other medications are not effective. Dietary supplements also lack evidence to support their use. While fibromyalgia can last a long time, it does not result in death or tissue damage.Fibromyalgia is estimated to affect 2–8% of the population. Women are affected about twice as often as men. Rates appear similar in different areas of the world and among different cultures. Fibromyalgia was first defined in 1990, with updated criteria in 2011. There is controversy about the classification, diagnosis and treatment of fibromyalgia. While some feel the diagnosis of fibromyalgia may negatively affect a person, other research finds it to be beneficial. The term "fibromyalgia" is from New Latin fibro-, meaning "fibrous tissues", Greek μυώ myo-, "muscle", and Greek άλγος algos, "pain"; thus, the term literally means "muscle and fibrous connective tissue pain".