Steadman estimates that insanity pleas were entered in 0.17 percent of New York State's 127,068 felony cases in 1978.
Successful insanity defendants share certain characteristics. They are mostly male, white, middle-aged, and unmarried. The vast major- ity are either unskilled or unemployed. Their crimes vary from state to state: More than half of New York's criminally insane are murderers, but only one-quarter of New Jersey's are. Assault and burglary offenses are common; sex offenders account...