Multiple sclerosis (MS) is an inflammatory disease in which the fatty sheaths around the nerves of the brain and spinal cord are damaged, leading to a broad array of signs and symptoms. Disease onset usually occurs in young adulthood, and it is more common in women. Almost any neurological symptom can appear with the disease, and often progresses to physical and mental disability. MS takes several forms, with new symptoms occurring either in discrete attacks or slowly worsening over time. Between attacks, symptoms may go away completely, but permanent neurological problems usually occur, especially as the disease advances.