title: Suicide risk among individuals with sleep disturbances in Japan: a case-control psychological autopsy study.
abstract: OBJECTIVE
  This case-control psychological autopsy study aimed to explore a relationship between sleep disturbances and suicide among Japanese, as well as determine the importance and usability of screening for sleep disturbances in suicide prevention.
  
  
  METHODS
  A semi-structured interview was conducted with the close family members of 49 adult suicide completers and 145 gender-, age-, and residential municipality-matched living controls. The survey included sections on demographics, sleep disturbances, and mental disorders. Conditional logistic regression analyses were performed to compare sleep disturbance prevalence between the two groups.
  
  
  RESULTS
  A significantly higher prevalence of sleep disturbances was found among the suicide group (75.5%) compared to the controls (11.0%) (odds ratio [OR]=21.6, p<0.001). The association remained significant after adjusting for mental disorders (OR=12.7, p<0.001). The population attributable risk percent of suicide associated with sleep disturbances and mental disorders was estimated to be 56.4% and 35.3%, respectively.
  
  
  CONCLUSIONS
  The study confirmed that sleep disturbances are an important risk factor of suicide, independent of mental disorders. Sleep disturbances accounted for a greater proportion of suicide cases than did mental disorders in the Japanese population given the higher prevalence, and could thus be considered an important target in suicide prevention in Japan.
authors.affiliation: National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira-shi, Tokyo 187-8553, Japan. Electronic address: mkodaka@ncnp.go.jp.
authors.forename: Manami
authors.initials: M
authors.lastname: Kodaka
authors.affiliation: National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira-shi, Tokyo 187-8553, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira-shi, Tokyo 187-8553, Japan; Department of Child Studies, University of Niigata Prefecture, 471 Ebigase, Higashi-ku, Niigata-shi, Niigata 950-8680, Japan.
authors.forename: Yotaro
authors.initials: Y
authors.lastname: Katsumata
authors.affiliation: National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira-shi, Tokyo 187-8553, Japan; Hyogo Institute for Traumatic Stress, 1-3-2, Kaigan-dori Wakihama, Chuo-ku, Kobe, Hyogo 651-0073, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Akazawa
authors.affiliation: National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira-shi, Tokyo 187-8553, Japan.
authors.forename: Hisateru
authors.initials: H
authors.lastname: Tachimori
authors.affiliation: Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Norito
authors.initials: N
authors.lastname: Kawakami
authors.affiliation: Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Eguchi
authors.affiliation: Mental Health Center of Yokohama, 6F, 18 Nihonodori, Naka-ku, Yokohama-shi, Kanagawa 231-0021, Japan.
authors.forename: Norihito
authors.initials: N
authors.lastname: Shirakawa
authors.affiliation: National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira-shi, Tokyo 187-8553, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Takeshima
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002423:Cause of Death; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D007406:Interview, Psychological; D007564:Japan; D008297:Male; D008403:Mass Screening; D001523:Mental Disorders / Q000401:mortality / Q000523:psychology; D008875:Middle Aged; D012307:Risk Factors; D012893:Sleep Wake Disorders / Q000401:mortality* / Q000523:psychology*; D013405:Suicide / Q000523:psychology* / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: Case–control; Japan; Mental disorder; Population attributable risk; Psychological autopsy; Sleep disturbance; Suicide; Suicide prevention