Myalgic Encephalomyelitis / Chronic Fatigue Syndrome (ME/CFS) and Fibromyalgia Syndrome (FMS) are complex illnesses that can be debilitating. There is a wide overlap of symptoms in ME/CFS and FMS. Many believe that they are variants of the same or similar disease process or pathogenesis. ME/CFS and FMS are distinguished from one another on the basis of symptom balance. ME/CFS patients have greater post-exertional malaise and/or fatigue, more severe fatigue, cognitive dysfunction, and immune dysfunction. FMS patients have greater pain and musculoskeletal dysfunction.

Although ME/CFS and FMS share a number of symptoms, ME/CFS is commonly triggered by a viral infection, whereas FMS is commonly triggered by a physical trauma, most often involving the spine.

A number of other illness have many symptoms in common with ME/CFS and or FMS.

A few of them are:

Gulf War Ilness

Post Polio Sequelae 

Lyme Disease

Multiple Chemical Sensitivities