What is an Insanity Defense?

We see it on television all the time: “Not guilty by reason of insanity” a judge thunderously booms from the bench, smashing his gavel down and allowing someone suspected of a heinous crime to walk away. But just how common is this in real life and what does it take to be considered legally insane?

In common criminal legal defense practice, the insanity defense is seldom used. It is considered by many defense attorneys to be a last resort. Proving someone was insane during the commission of a crime is difficult and juries have a difficult time believing someone committed a criminal act but shouldn’t be held responsible.

So what exactly has to be proven for the insanity defense to work? Often called the McNaughten rule, the defense must show the court that the defendant didn’t understand the difference between right and wrong at the commission of the crime. This is significantly more difficult than one might think, hence its rare appearance in criminal courts.

This case outlined here from the Des Moines Register shows just how difficult it can be to make this defense work. The defendant is accused of first degree murder. Evidence against him includes audio recordings of his confession and bizarre ramblings during police questioning.

As the report points out, no one denies the defendant may suffer from mental illness. This, however, isn’t enough to pass the McNaughten Rule itself. Regardless of whether a defendant suffers from extreme depression or even schizophrenia, the court must still determine that he/she didn’t know right from wrong when the crime was committed.

Another related defense, only present in some states, is referred to as an “irresistible impulse” defense (sometimes called temporary insanity in the media). This situation is slightly different in that the defense must show the accused may have understood the gravity of their offense but could not control their actions at the time. This defense is typically used in what is often called “crimes of passion”.

When you are facing criminal charges it is rational to examine all of your possibilities. More than likely, you weren’t legally insane at the commission of your act. However, there are often legal defenses that would apply in your case.

Most legal defense strategies aren’t quite so dramatic. Often, you really just need is an experienced criminal defense lawyer to thoroughly evaluate the facts of your case, and the evidence against you, to come up with the best opportunity to defend you in court.

About David Matson