About two-thirds of inmates with a serious mental illness in the Department of Justice’s (DOJ) Federal Bureau of Prisons (BOP) were incarcerated for four types of offenses—drug (23 percent), sex offenses (18 percent), weapons and explosives (17 percent), and robbery (8 percent)—as of May 27, 2017. GAO’s analysis found that BOP inmates with serious mental illness were incarcerated for sex offenses, robbery, and homicide/aggravated assault at about twice the rate of inmates without serious mental illness, and were incarcerated for drug and immigration offenses at about half or less the rate of inmates without serious mental illness. GAO also analyzed available data on three selected states’ inmate populations and the most common crimes committed by inmates with serious mental illness varied from state to state due to different law enforcement priorities, definitions of serious mental illness and methods of tracking categories of crime in their respective data systems.
