Famous Insanity Cases Shed Light on James Holmes: Will He Plead Not Guilty?

James Holmes' lawyers have stated that they believe their client is insane and may pursue an insanity defense. While that course of action seemed obvious to many, other research suggests that an insanity plea is not as popular as it may seem and may be difficult to prove.

In early August, James Holmes' lawyers agreed that their client was mentally insane although it was uncertain to what extent. While Holmes' lawyers delve further into their client's mental history in order to decide how they will plea for the killings that took place in Aurora, Colorado, some have become dissatisfied with the idea that Holmes could plead insanity.

"This man is not mentally ill! He is a very smart man," Maddy argued on the TMZ blog. "Everything he did was him becoming the joker. Yea little crazy maybe? He knows right from wrong, but he does not care."

While claiming insanity may seem like a popular defense however, according to Laws.com the insanity plea is used in less than one percent of criminal cases. That fact however, has not stopped high publicity cases from drawing a significant amount of attention to the insanity plea.

Jeffrey Dahmer pleaded "not guilty" by reason of insanity in the 1990's although his plea was rejected and he was convicted on 15 counts of murder. John Wayne Gacy also attempted an insanity plea in the 1980's after he raped and killed over 33 young boys, but was also denied and convicted. Andrea Yates, the mother who drowned her five children, was found not guilty by reason of insanity in 2006.

Lawyers may have a difficult time proving that Holmes is insane however, because in Colorado they will be required to prove that he was insane while he was committing the crimes.

"That's a problem, particularly when you're talking about mental illness," said Quin Denvir, a former federal public defender who worked on a similar insanity plea in Colorado, according to the Denver Post. "It's a really imprecise area. You have to meet a certain standard of proof based on expert testimony, and that's much more difficult."