The defense in criminal proceedings arises when the conditions exist to deny specific elements of the crime: the actus reus when the acts are involuntary, the mens rea when the accused is not aware of the scope of the act their conduct, or both. These defenses will mitigate or eliminate liability arising from a criminal offense. Insanity, automatism, and diminished responsibility are examples of such defenses. They each share characteristics but can be distinguished in their scope and application. Insanity, automatism, and diminished responsibility all play a significant role in cases where the defendant's mind is abnormal while committing a crime. The definition of abnormal will be reviewed in relation to each defense. To identify how these three defenses compare and contrast, it is first important to understand their definition and application. The appropriate defense will be used once the facts of the cases have been distinguished and have passed the legal tests. The legal test for insanity is established in the M'Naghten case as mentioned above: "to establish a defence... of insanity it must be clearly shown that, at the time he committed the act, the accused party was suffering from such defect of reason, due to disease of the mind, from not knowing the nature and quality of the act he was doing, or if he knew it, from not knowing that he was doing what was wrong. Specifically, the defect of reason occurs when the defendant is incapable of exercising normal reasoning requires the instability of reasoning rather than the failure to exercise it when the exercise of reason is possible clinically depressed and in a moment of distraction, he stole objects from a supermarket... in the middle of paper... the result will be an absolute acquittal, on the premise that no act is punishable if carried out involuntarily more similar to insanity than automatism as the court has discretion in sentencing; however, the outcome of the defense can be distinguished from both. A positive outcome when the defense is raised is the reduction of responsibility from murder to manslaughter and consequently the removal of the mandatory sentence of life imprisonment. The court will have discretion regarding the sentence to be passed, which may include absolute discharge, hospitalization, protective order or life imprisonment. This defense was created to further support the principle of defenses and gives the court broad discretion. The insanity defense was too narrow in definition and did not protect those who killed those who did not comply with the M'Naghten Rules..