Method: The Great East Japan Earthquake on March 11, 2011, was a catastrophic disaster. The investigators studied psychiatric change among a population of psychiatric outpatients in Tochigi prefecture, located ~160 km (~100 miles) southeast of the Fukushima nuclear power plant, in an area that suffered moderate damage from the earthquake. A total of 328 psychiatric outpatients were enrolled and were grouped into the diagnostic categories F2 (schizophrenic, schizotypal, and delusional disorders), F3 (affective disorders), and F4 (neurotic, stress-related, and somatoform disorders). All diagnoses were made using International Classification of Diseases (ICD) 10 criteria. Changes in symptoms were measured as a change in psychotropic medication after the disaster.