Differential diagnosis of memory impairment in areas affected by a natural disaster:a case report.

We treated a man with a chief complaint of memory impairment after the Great East Japan Earthquake. Initially, he was diagnosed with dementia. However, after several tests, neither could a definitive diagnosis of dementia be reached, nor was there any apparent evidence for depression, epilepsy, delirium, or internal medicine diseases. During the earthquake, the patient experienced the severe trauma of watching his wife being swept away by a tsunami. Furthermore, he experienced separation from his family. Because of this traumatic experience, we suspected that dissociative disorder was involved in the development of the memory impairment and thus, we switched to treatments focusing on emotional support. Subsequently, the patient's memory impairment gradually improved. The present case demonstrates the importance of considering dissociative disorders when examining a patient with memory impairment in areas affected by disasters.