The impact of the Great East Japan earthquake on mandatory psychiatric emergency hospitalizations in Tokyo: a retrospective observational study

On 11 March 2011, the eastern part of Japan was struck by a magnitude 9.0 quake. About 20 000 people were killed or weremissing, and a nuclear crisis followed. In Tokyo, people were indirectly exposed to the earthquake and nuclear crisis by TV broadcast. The aim of our study was to evaluate the potential effect of the series of catastrophes on psychiatric emergency hospitalizations in Tokyo. Clinical records of patients who were mandatorily admitted to Tokyo Metropolitan Matsuzawa Hospital by law because of urgent risk to self or others were reviewed. Records regarding the 2 years of investigation, which include the 6 months after the earthquake, were reviewed. The six months after the earthquake were compared with the eighteen months before the earthquake in clinical and demographic data using independent t-tests or χ(2) tests. During the 6 months before and after the earthquake, 97 and 127 people were mandatorily admitted. χ(2) Tests demonstrated a significant increase in the number of patients after the earthquake (P=0.045), attributable to the significant increase in the number of patients with schizophrenia after the earthquake (P=0.011, 32 vs 56), whereas there were no significant differences in the number of patients with other diagnoses between those two periods. Independent t-tests revealed that patients admitted after the earthquake had marginally significantly shorter periods of education compared with those admitted before the earthquake (13.78 vs 12.82 years, P=0.084). This work suggests that patients with schizophrenia were more sensitive to indirect exposure to the earthquake and that a shorter period of education was a potential risk factor.