In 2014, the town of Waukesha, Wisconsin was rocked by the attempted homicide of a young girl by two of her classmates. The 12-year-old girls who allegedly stabbed their friend multiple times claimed they did so in order to please a mythical, evil character they believed was real. Both were charged with attempted first-degree intentional homicide in the so-called Slender Man case.
One defendant originally pleaded not guilty, but eventually changed her plea to not guilty by reason of mental instability or defect, commonly referred to as the "insanity" plea. The other also entered an insanity plea; she had been diagnosed with schizophrenia, a mental condition from which her father also suffered.
What constitutes insanity in a court of law?
An official diagnosis of whether a defendant is insane must be offered by medical professionals. The court will usually order the defendant to be tested by more than one physician or psychologist. Wisconsin Statute 971.15(1) dictates that a defendant is not responsible for criminal action if, at the time, due to "mental disease or defect the person lacked substantial capacity either to appreciate the wrongfulness of his or her conduct or conform his or her conduct to the requirements of law." Summarily, the defendant must be determined to have been unable to differentiate between right and wrong due to mental instability at the time they committed the crime.
In the case above, the defendant who changed her plea did so based on the premise that she became so obsessed with the made-up character she became delusional. She was, in fact, diagnosed with a delusional disorder.
There's good reason why the defendants' attorneys argued to have the girls tried in juvenile court, even though such a case would typically be tried in adult court. If found guilty as sane juveniles, the girls could be imprisoned until they turned 25. If found not guilty by reason of insanity, they would be sent to a hospital.
Because the girls will be tried as adults, they face the possibility of spending decades in prison. But if found not guilty by reason of insanity, they will be sent to a mental facility. Juvenile defendants who suffer from mental disorders may seem normal -- and guilty, but an experienced criminal defense attorney and a proper diagnosis can help them to get the treatment they need.