What principle was discussed in DPP v. Kelly regarding insanity defenses?

In DPP v. Kelly, the court addressed the principle that the burden of proof in insanity defenses falls on the defendant. This principle is significant because it shifts the responsibility onto the defendant to establish, on the balance of probabilities, that they were insane at the time of committing the offense. The legal definition of insanity in this context relies on understanding the mental state of the defendant, and it emphasizes the need for the defendant to present evidence demonstrating their insanity. This includes possibly bringing forward expert testimony or psychiatric evaluations to support their claim. Understanding this principle is crucial for both defense and prosecution in cases involving mental health defenses, as it sets the groundwork for how the insanity defense is approached in Irish criminal law.