[1] Univ Tsukuba, Inst Clin Med, Dept Psychiat, Tsukuba, Ibaraki 3058575, Japan
[2] Kyorin Univ, Sch Med, Dept Geriatr Med, Hachioji, Tokyo, Japan
[3] Univ Tokyo, Grad Sch Med, Dept Geriatr Med, Tokyo 1138654, Japan
[4] Tokyo Med Univ, Dept Geriatr Med, Tokyo, Japan
[5] Tokyo Med Univ, Hachioji Med Ctr, Tokyo, Japan
[6] Univ Yamanashi, Hlth Care Ctr, Yamanashi, Japan
[7] Gunma Prefectural Psychiat Med Ctr, Gunma, Japan
[8] Yokohama City Univ, Med Ctr, Ctr Psychiat, Yokohama, Kanagawa, Japan