This study aimed to examine the effect of Hurricane Sandy on Long Island mental health emergency department (ED) visits and to determine whether these visits varied according to patient demographics or geographic area and intensity of the impact.

Individual-level de-identified data were extracted from the Statewide Planning and Research Cooperative System from New York State ED visits from October 1 to December 2012 for residents of Nassau and Suffolk counties in Long Island. The dates of the ED visits were grouped into 4 periods: (1) pre-Sandy, October 1–28; (2) during Sandy, October 29; (3) post-Sandy I, October 30 to November 1; and (4) post-Sandy II, November 2–30.

A total of 126,337 ED visits were recorded among 23 EDs. A significant drop in volume was observed on October 29; 399 more ED visits for physical health diagnoses were identified in the post-Sandy I period than in the pre-Sandy period. “Diseases of the respiratory system” was the only diagnosis group that showed a positive trend in the post-Sandy I period compared with the pre-Sandy period (increase of 4%). No significant changes in mental health visits were observed after Sandy landfall.

This analysis suggests that the critical temporal window during which ED resources should be increased is in the immediate aftermath of a hurricane. (Disaster Med Public Health Preparedness. 2016;10:344–350)