Dysfunctional syndromes and fibromyalgia: a 2012 critical digest.

Medically 'unexplained' chronic disorders remain a challenge for clinicians because the patients with these syndromes have a wide range of symptoms, including pain, impaired concentration, sleep disturbances, fatigue and mood disorders, as well as functional problems and difficulties in carrying out the activities of daily living. Such disorders are the result of a complex physiological interaction of central and peripheral nervous signaling that leads to a highly individual symptom complex, although some of them seem to be related to one another, especially in terms of the mechanism of chronicity and pain amplification, and the co-occurrence of fatigue, sleep alterations, mood disturbances and cognitive impairment. This review will discuss the recent literature concerning the most common dysfunctional disorders: fibromyalgia syndrome, myalgic encephalomyelitis/chronic fatigue syndrome, and irritable bowel syndrome.