Is Mental Illness a Defense in Criminal Cases?

Although several states do not allow mental illness as a defense in criminal cases, New York does allow such a defense. This is typically called the “Insanity defense.” If you’ve been charged with a crime in New York, and you believe that your lack of mental capacity at the time may be at issue, Cody Warner, NYC criminal lawyer, may be able to help. 

Mental Illness As A Defense

New York Penal Law Section 40.15 sets forth the requirements necessary to prove a defendant’s lack of mental culpability. If you can show that you lacked the necessary capacity to understand the nature and consequences of your actions, or you were incapable of knowing that your acts were wrong or improper, you may be relieved of criminal responsibility.

The insanity defense is known as an “affirmative defense,” because the defense has the responsibility to affirm and establish the defense. The defense must provide evidence that establishes the defense by a preponderance of the evidence. A “Preponderance of the evidence” is established when the factfinder determines that it is more likely than not that a claim is true.

The federal insanity defense, set forth in 18 U.S.C. Section 17, is applicable for people charged with federal crimes. Under the federal insanity defense, the defendant must prove by “clear and convincing evidence” that he was unable, at the time of the commission of the crime, to understand the nature and quality or the wrongfulness of his actions due to a mental defect. “Clear and convincing evidence” means that the evidence is substantially more likely to be true than untrue.

Procedural Requirements Which Must Be Met

Mounting a successful insanity defense requires the defendant to overcome several difficult obstacles. First, the prosecution must be notified that you intend to offer the insanity defense, and you will be subject to a mental evaluation. Any statements you make during this exam can be used against you.

In addition, you must waive the physician-patient privilege and the Fifth Amendment privilege against self-incrimination in regard to your mental health.

Psychiatric Evidence Required To Prove The Insanity Defense

Psychiatric evidence is generally required to prove the insanity defense. Many different mental and psychiatric illnesses suffered by the defendant may help prove the defense, including:

• Schizophrenia
• Personality Disorders
• Acute Psychotic Disorder
• Hallucinations
• Delirium Tremens
• Obsessive-Compulsive Disorder
• Organic Brain Damage
• Post-Traumatic Stress Disorders
• Brain Tumors
• Organic Brain Disorders.

This is not a comprehensive list, and other psychiatric illnesses may be used as part of an insanity defense.

To prevail on an insanity defense, the defendant must be able to convince a jury that his disordered or distorted thinking was so serious that the defendant was detached from reality during the crime. Even when mental illness played a significant role in the crime, judges and juries are often reluctant to believe that the defendant was actually totally unable to understand the nature and quality of the wrongdoing.

It is estimated that the insanity defense is used in less than 1% of felony cases, and is successful in less than 25% of those cases. When the insanity defense is successful, the defendant typically has a previous diagnosis of mental illness.

If a defendant successfully uses the insanity defense to relieve himself of criminal liability, this does not mean that the defendant will go free. Typically, there will be a period of time that the person must spend in a mental health facility for evaluation and perhaps treatment. In some cases, the person may be released to a family member or other responsible party.

It’s important not to confuse the insanity defense with competency to stand trial. Competency to stand trial deals with the ability of a defendant to comprehend the nature of the actions against him at the time of trial. If a defendant is found to be incompetent to stand trial, that does not have any bearing on the mental competency of the defendant during the commission of the crime in question.

NYC Criminal Lawyer Cody Warner Can Develop the Right Defense Strategy for Your Case 

Contact NYC criminal lawyer Cody Warner to learn more about whether a mental illness defense applies in your case. Cody offers free consultations and can determine the best path forward for your case. Contact Cody today.