Task: Text Simplification
Input (English): The insanity defense , also known as the mental disorder defense , is an affirmative defense by excuse in a criminal case , arguing that the defendant is not responsible for his or her actions due to an episodic or persistent psychiatric disease at the time of the criminal act .
Output (English): In criminal trials , the insanity defense is the claim that the defendant is not responsible for his or her actions due to a mental illness .