[1] Yonsei Univ, Coll Med, Inst Behav Sci Med, Seoul, South Korea
[2] Yonsei Univ, Coll Med, Dept Psychiat, Yonsei Ro 50, Seoul 03722, South Korea
[3] Univ Calif Los Angeles, Cousins Ctr Psychoneuroimmunol, Semel Inst Neurosci & Human Behav, Los Angeles, CA USA
[4] Univ Calif Los Angeles, David Geffen Sch Med, Dept Geriatr, Los Angeles, CA 90095 USA