To consider how then currently used drug therapies for MS in veterans, e.g., Interferon beta-1b, interferon beta-1a and glatiramer acetate impact health related quality of life (HRQoL), physical function and disability and use of health care resources within the VA. Comparisons with other groups of veterans with specific chronic medical conditions will be made in order to develop a model of health care utilization based on indices derived from disability and impairment evaluations and HRQoL instruments.