The concept of insanity is legally defined as the ability of the person to understand right from wrong when committing a crime. The person must not be able to distinguish imagination from reality or is subject to loss of serious control or uncontrollable behavior (Howes, 2009). This definition is more of a legal definition than medical because the medical community does not classify a person as being insane except in the instance of legal necessity. Medicine views mental illness in terms of specific illnesses or mental defects (Howes, 2009). Within this context, the legal idea of insanity can be distinguished depending on the diagnosis. For example, if a man kills a person because he was suffering from delusions caused by a mental illness which causes him to see the person as a monster, then he can be found to be insane in the legal sense. The problem with this difference in definition is that there is a large grey area which must be determined via professional diagnosis. For instance, the determination of insanity becomes less clear when one views it through the lens of intention. If a person is diagnosed with a mental illness such as Alzheimer’s and kills his or her spouse. This does not always mean the person was insane because if it can be shown that the person had an intention and that the illness was not so far progressed that it precluded him or her from understanding the difference between wrong and right, then this person may be found fit to stand trial and be found guilty of the crime of murder. This large grey area makes the insanity defense open to interpretation by professionals and leaves a large subjective area in the determination of guilty or innocence.
Howes, R. (2009) The definition of insanity is… Retrieved from https://www.psychologytoday.com/blog/in-therapy/200907/the-definition-insanity-is