The insanity defense basically amounts to an argument that you do not understand the criminality of your actions or are unable to control your behavior. Insanity isn't a carte blanche defense that covers every single crime or case; it is a limited defense that is actually only used on occasion.
The insanity defense puts the burden on you to prove that you were unable to conform your behavior within the confines of the law. It also amounts to conceding that your actions may have already been illegal and as such can be a risky defense. However, if you believe you suffer from a mental illness then this may be the correct litigation strategy.
There are several tests that are used throughout the United States. Most individual states utilize a combination of these various tests. The three primary tests are:
The M'Naughten Rule generally says that the defendant failed to distinguish right from wrong or did not understand the wrongness of their actions.
The Model Penal Code Test combines the M'Naughten rule with a diagnosed mental defect.
The Irresistible Impulse Test means that, due to a mental illness, the defendant is unable to control his impulses.
If you are charged with a crime and you believe that your actions may have been the result of a mental illness or condition then you might want to speak with a criminal defense attorney to review your options. The insanity defense is a tricky needle to thread because of the stigma associated with mental illness and the burden of proof. Employing this defense is a serious step to take, so it is best to speak with an attorney before deciding how to plan your defense.