Acute and chronic effects of sarin exposure from the Tokyo subway incident.

The Tokyo subway sarin attack was the second documented incident of nerve gas poisoning in Japan. The St. Luke's International Hospital received 640 patients on the day of the attack. Reduction in plasma cholinesterase (ChE) activity was generally associated with the severity of acute signs of toxicity. With time and treatment, the value rose quickly. To evaluate possible residual signs of symptoms 1 year after the attack, we sent questionnaires to the victims; of 303 respondents, 45% still had some symptoms including eye problems, easy fatigability, headache, and fear. Therefore, we conducted a study in collaboration with investigators at the Tokyo University Department of Public Health to evaluate possible long-term neuropsychological sequelae. The findings suggest the need to closely follow such patients for possible persistent functional changes.