Introduction: In 2015, an estimated 43.4 million Americans aged 18 and older suffered from a behavioral health issue. Accurate estimates of the number of psychiatrists, psychologists, and psychiatric nurse practitioners are needed as demand for behavioral health care grows. Methods: The National Plan and Provider Enumeration System National Provider Identifier data (October 2015) was used to examine the supply of psychiatrists, psychologists, and psychiatric nurse practitioners. Providers were classified into three geographic categories based on their practicing county (metropolitan, micropolitan, and non-core). Claritas 2014 U.S. population data were used to calculate provider-to-population ratios for each provider type. Analysis was completed in 2016. Results: Substantial variation exists across Census Divisions in the per capita supply of psychiatrists, psychologists, and psychiatric nurse practitioners. The New England Census Division had the highest per capita supply and the West South Central Census Division had among the lowest supply of all three provider types. Nationally, the per capita supply of these providers was substantially lower in non-metropolitan counties than in metropolitan counties, but Census Division disparities persisted across geographic categories. There was a more than tenfold difference in the percentage of counties lacking a psychiatrist between the New England Census Division (6%) and the West North Central Census Division (69%). Higher percentages of non-metropolitan counties lacked a psychiatrist. Conclusions: Psychiatrists, psychologists, and psychiatric nurse practitioners are unequally distributed throughout the U.S. Disparities exist across Census Divisions and geographic categories. Understanding this unequal distribution is necessary for developing approaches to improving access to behavioral health services for underserved populations. (C) 2018 American Journal of Preventive Medicine. Published by Elsevier Inc.
