Chronic Fatigue Syndrome, more accurately known as Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), is a complex, chronic, and often devastating multi-system illness. It is characterized by profound, disabling fatigue that is not improved by rest and can be worsened by physical or mental exertion. This is not simply feeling tired; it's a persistent state of exhaustion that significantly interferes with daily activities and quality of life. Key Characteristics and Core Symptoms: ME/CFS is distinguished by a unique combination of symptoms, which can fluctuate in severity and duration from person to person. The core symptoms typically include: Profound Fatigue: This is the hallmark of ME/CFS. It's a severe, new-onset fatigue that has lasted for at least six months (three months in children and adolescents). It is not the result of ongoing exertion, not substantially relieved by rest, and causes a significant reduction in previous levels of activity (personal, soci...