What Is the Legal Definition of Insanity?

Definition of Insanity Under California Law

Although Albert Einstein is often credited for saying, “The definition of insanity is doing the same thing over and over again and expecting different results,” insanity in the eyes of the law is something entirely different. According to the law, when people are said to be insane, it means they are in a state of derangement which manifests as a lack of understanding or an incapacitated mind.

An individual is considered legally insane under California law if they do not comprehend the nature of their actions or they are unable to distinguish between what is right and wrong. The law also requires a certain level of mental capacitation for individuals to enter into certain relationships or to be held responsible for their behaviors.

Although psychological analysis is a factor in determining if a person is legally insane, there are times when a person can be considered psychotic but still fall short of meeting the legal definition for insanity.

What Is the M’Naghten Test?

The M’Naghten test is a cognitive test that assesses the thought processes and perceptions the defendant had at the time the crime was committed. If the person suffered from a mental disease at the time of the offense, then they are considered legally insane because they did not know that their actions were illegal or wrong.

If a defendant’s mental state meets the M’Naghten test, then it doesn’t matter if their mental state was permanent or temporary. Both temporary and permanent insanity qualify for the California insanity defense.

The Burden of Proof & Preponderance of the Evidence

In most criminal trials, the prosecutor has the burden of proof when it comes to the question of guilt or innocence. However, California’s insanity defense is considered an “affirmative defense,” which means the defendant has the burden of proving they were insane at the time of the crime by a “preponderance of the evidence” and should be excused for their actions. Under the preponderance of evidence standard, juries must rule against the defendant if neither side has the stronger argument for the insanity defense.

How Do I Plead Not Guilty by Reason of Insanity in California?

In California, there are two ways to initiate an insanity defense. You can plead both “not guilty” and “not guilty by reason of insanity,” or you can admit to committing the crime but still enter a plea of not “guilty by reason of insanity.”

Our Compassionate LA Criminal Defense Attorneys Proudly Advocate for Mental Health Defendants

At Lessem & Newstat, LLP we have the knowledge and skills you need to confidently take an insanity defense to court if appropriate. Our dedicated attorneys are passionate about protecting the interests of criminal defendants with mental health issues.

We have a thorough understanding of the history of the M'Naghten Rule and know what it takes to successfully execute a not guilty by reason of insanity plea, so you can trust that we will have your back at each phase of the legal process.

If you would like to speak to a Los Angeles criminal defense lawyer at Lessem & Newstat, LLP, please call us today at (800) 462-7160 or contact us online to schedule a case consultation.