A new study dispels the myth that the most frequent users of hospital emergency rooms are people with mental illness and substance use disorders. This population accounts for only a small percentage of visits, the researchers found.

The study looked at emergency room visits made by more than 212,000 Medicaid patients in New York City since 2007, HealthDay reports. The researchers found patients who frequently use the ER tend to have multiple chronic health conditions and many hospitalizations.

“Urban legend has often characterized frequent emergency department patients as mentally ill substance users who are a costly drain on the health care system and who contribute to emergency department (ED) overcrowding because of unnecessary visits for conditions that could be treated more efficiently elsewhere,” the researchers wrote in the journal Health Affairs. “This study of Medicaid ED users in New York City shows that behavioral health conditions are responsible for a small share of ED visits by frequent users, and that ED use accounts for a small portion of these patients’ total Medicaid costs.”