Sleep disorders and suicidal ideation in Japanese patients visiting a psychosomatic clinic in a university hospital. - Yoshimasu, Kouichi; Sugahara, Hideyo; Akamine, Mariko; Kondo, Tetsuya; Fujisawa, Kanichiro; Tokunaga, Shoji; Kiyohara, Chikako; Miyashita, Kazuhisa; Kubo, Chiharu (Sleep & Biological Rhythms, 2006)