Insanity pleas are rare, but defendants in criminal trials frequently tell judges and juries that mental illness limited their capacity for rational thought.
The classic example is the "Twinkie defense," which comes from the 1979 trial of former San Francisco Supervisor Dan White, who shot and killed Mayor George Moscone and Supervisor Harvey Milk, a noted gay-rights activist.
A defense attorney argued that White's depression, enhanced by a diet of junk food and soda, made him unable to form the intent required for a murder conviction. Twelve jurors found White guilty of manslaughter rather than murder.
Recent cases in Stanislaus County Superior Court have been less dramatic.
Juries sometimes opt for a lesser charge than the one lodged by the district attorney's office, and judges sometimes agree that mental illness is a mitigating factor when they impose sentence, but offenders rarely get a free pass.
Here are a few examples:
— Angel Cabanillas was 14 when he shouted gang slogans and opened fire on strangers during a June 2006 shooting spree in south Modesto. He had been released from Juvenile Hall just five days earlier, without antipsychotic medications he needed for depression and hallucinations. Jurors recently found him guilty of second-degree murder as well as multiple counts of attempted murder and assault with a firearm. Now 17, Cabanillas faces life in prison. His sentencing is pending.
— Kyle Eugene Purdy, 43, was high on methamphetamine and afraid of imaginary assassins in December 2004 when he commandeered two vehicles and crashed into several others near Turlock High School. He had been dropped off at Stanislaus County Behavioral Health Center hours earlier by California Highway Patrol officers who spotted him on Geer Road, talking to a tree. Purdy blamed the mental health system for his crime, arguing that he would not have harmed anyone had he not been detained by authorities. A drug-induced psychosis is not a defense to a crime; a judge sentenced Purdy, who was on parole for other crimes, to nearly 20 years in prison.
— One of the most sympathetic defendants to come through the justice system in recent years is Modesto homemaker Danise McFadden, 40, who was naked and in the midst of a mental health crisis in November 2005 when she caused a fatal wreck. McFadden was driving 74 mph when she slammed into a truck that was stopped at a stop light, killing a family man who was on his way to work. Her remorse was palpable, but she still had to serve 52 days behind bars for misdemeanor vehicular manslaughter.