Insomnia as a sequela of sarin toxicity several years after exposure in tokyo subway trains

Tomoyuki Kawada, Masao Katsumata, Hiroko Suzuki, Qing Li, Hirofumi Inagaki, Ari Nakadai, Takako Shimizu, Kimiko Hirata, Yukiyo Hirata

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


More than 5,000 passengers on Tokyo subway trains were injured with toxic chemicals including the nerve gas "sarin" on March 20, 1995. The purpose of this study was to identify the effect of sarin exposure on insomnia in a cross-sectional study. A self-administered questionnaire concerning sleep-related items was distributed to victims of sarin exposure in October and November, 2003. Questionnaires were completed by 161 of the 163 participants (98.8%), who were selected from 1,500 subjects. Among them, the authors selected 75 women 30 to 69 years of age. Control participants were collected from inhabitants living in Maebachi City, Gunma Prefecture, Japan. For the younger exposed group (under 50 yr. of age), percentages of poor sleep, difficulty falling asleep, intermittent awakening, early morning awakening, a feeling of light overnight sleep, and insomnia were significantly higher than those for the control group. In contrast, the older exposed group (ages 50 to 69 years) had significantly higher prevalence of poor sleep, a feeling of light overnight sleep, and early morning awakening for the exposed group when compared with the control group. The high prevalence of insomnia and insomnia-related factors for victims especially under 50 years of age suggests a need for research on sleep quality after sarin exposure. Although posttraumatic stress disorder is assumed to be a psychological effect of exposure to a toxic substance, a cause-and-effect relationship has not been established.

Original languageEnglish
Pages (from-to)1121-1126
Number of pages6
JournalPerceptual and motor skills
Issue number3 II
Publication statusPublished - 2005 Jun

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Sensory Systems


Dive into the research topics of 'Insomnia as a sequela of sarin toxicity several years after exposure in tokyo subway trains'. Together they form a unique fingerprint.

Cite this