Killings by persons who were insane, deranged or temporarily incapacitated mentally occur throughout this data set. The standard for proving insanity was the McNaghten test, the standard being that the actor did not know what he was doing or did not know that it was wrong. This standard is still used in most American jurisdictions today.
Medical treatment in public hospitals for the insane and mentally deranged was plagued by the same corruption and inefficiency which characterized other public health facilities in Chicago.
The first public mental hospital was part of the County Hospital.
For further reading: Thomas Neville Bonner, Medicine in Chicago, 1850-1950, U. Illinois Press, Chicago,1991.