The Tokyo subway sarin attack has long-term effects on survivors: A 10-year study started 5 years after the terrorist incident.

Aya Sugiyama,Yukio Kuroiwa,Toshihiko Matsuoka,Shinsuke Kimura,Junko Tanaka,Tomoyuki Akita,Masataka Nagao,Kazuaki Sakamune,Ryosuke Makita,Kenji Hashimoto

doi:10.1371/journal.pone.0234967

Abstract

ObjectivesThe Tokyo subway sarin attack in 1995 was an unprecedented act of terrorism that killed 13 people and sickened more than 6,000. The long-term somatic and psychological effects on its victims remain unknown.MethodsWe conducted analyses on the self-rating questionnaire collected annually by the Recovery Support Center (RSC) during the period from 2000 to 2009. The RSC is the only organization that has large-scale follow-up data about sarin attack victims. The prevalence of self-reported symptoms was calculated over 10 years. We also evaluated the prevalence of posttraumatic stress response (PTSR), defined as a score ≥ 25 on the Japanese-language version of the Impact of Event Scale–Revised. The multivariate Poisson regression model was applied to estimate the risk ratios of age, gender, and year factor on the prevalence of PTSR.ResultsSubjects were 747 survivors (12% of the total) who responded to the annual questionnaire once or more during the study period. The prevalence of somatic symptoms, especially eye symptoms, was 60–80% and has not decreased. PTSR prevalence was 35.1%, and again there was no change with time. The multivariate Poisson regression model results revealed “old age” and “female” as independent risk factors, but the passage of time did not decrease the risk of PTSR.ConclusionsAlthough symptoms in most victims of the Tokyo subway sarin were transient, this large-scale follow-up data analysis revealed that survivors have been suffering from somatic and psychological long-term effects.

Highlights

IntroductionDuring the morning rush hour on March 20, 1995, the nerve gas sarin (isopropyl methylphosphonofluoridate) was used in a terrorist attack on commuter subway trains in Tokyo, Japan
During the morning rush hour on March 20, 1995, the nerve gas sarin was used in a terrorist attack on commuter subway trains in Tokyo, Japan
We evaluated the prevalence of posttraumatic stress response (PTSR), defined as a score 25 on the Japanese-language version of the Impact of Event Scale–Revised

Summary

Introduction

During the morning rush hour on March 20, 1995, the nerve gas sarin (isopropyl methylphosphonofluoridate) was used in a terrorist attack on commuter subway trains in Tokyo, Japan. Tokyo Metropolitan Police Department reported that a total of 13 people were killed, and 6,226 people filed an injury report to the police. This was the largest terrorist attack targeting civilians using a warfare nerve agent in modern times. In the case of sarin, this symptom arises in 50% of exposed people at about 3 mgmin/m3. Higher exposures cause more significant incapacitation, eventually leading to death for 50% of exposed people at 70–100 mgmin/m3 [1]

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