In Illinois, if you're a defendant seeking the affirmative defense of not guilty by reason of insanity (NGRI), you need to demonstrate several elements to prove your case. These elements are outlined in the relevant statute and have been further clarified through case law. Here's what you need to demonstrate: Mental Disease or Defect: You must establish that, at the time of the offense, you suffered from a mental disease or defect. This mental illness or condition must have impaired your ability to appreciate the criminality of your conduct or to conform your conduct to the requirements of the law. Lack of Capacity to Appreciate Criminality: You need to demonstrate that, due to the mental disease or defect, you lacked substantial capacity to appreciate the criminality of your conduct. This means showing that you did not understand that your actions were wrong according to societal or legal standards. Lack of Capacity to Conform Conduct: Additionally, you must show that, because of the mental disease or defect, you lacked substantial capacity to conform your conduct to the requirements of the law. This means you were unable to control your behavior in accordance with legal standards, even if you understood that your actions were wrong. Preponderance of the Evidence: The burden of proof rests with you as the defendant. You must establish the elements of the NGRI defense by a preponderance of the evidence. This means that you must demonstrate that it is more likely than not that you meet the criteria for the NGRI defense. It's important to note that seeking an NGRI defense in Illinois involves presenting evidence, including expert testimony from mental health professionals, to support your claim of mental illness or defect and its impact on your ability to appreciate the criminality of your conduct or to conform your conduct to the requirements of the law. Additionally, the specific requirements and procedures for presenting an NGRI defense may vary depending on the circumstances of your case and any relevant legal precedents. Therefore, consulting with an experienced criminal defense attorney who is familiar with Illinois law is essential to navigate the NGRI defense process effectively.