[1] Harvard Univ, Brigham & Womens Hosp, Sch Med, Dept Psychiat, Boston, MA 02115 USA
[2] Harvard Univ, Dept Neurol, Beth Israel Deaconess Med Ctr, Sch Med, Boston, MA 02115 USA
[3] Univ Toronto, Dept Psychiat, Toronto, ON M5S 1A1, Canada
[4] Natl Multiple Sclerosis Soc, New York, NY USA
[5] Cleveland Clin, Mellen Ctr, Cleveland, OH USA
[6] Northwestern Univ, Dept Prevent Med, Evanston, IL USA
[7] Univ Calgary, Dept Community Hlth Sci, Calgary, AB T2N 1N4, Canada
[8] Univ Calgary, Hotchkiss Brain Inst, Calgary, AB T2N 1N4, Canada
[9] VA Maryland Hlth Care Syst, Baltimore, MD USA
[10] Univ Kansas, Med Ctr, Dept Neurol, Kansas City, KS USA