1. VA Puget Sound Health Care System, VA Multiple Sclerosis Center of Excellence West, VA Center of Excellence in Substance Abuse Treatment and Education, Department of Rehabilitation Medicine, University of Washington, WA, USA,
2. VA Puget Sound Health Care System, VA Center of Excellence in Substance Abuse Treatment and Education, Department of Psychiatry and Behavioral Sciences, University of Washington, WA, USA
3. VA Puget Sound Health Care System, VA Multiple Sclerosis Center of Excellence West
4. VA Puget Sound Health Care System, VA Multiple Sclerosis Center of Excellence West, Department of Rehabilitation Medicine, University of Washington, WA, USA, Department of Epidemiology, University of Washington, WA, USA