This evolved into the concept of mens rea or "guilty mind " which is the component of a crime that looks at a person's state of mind. The first famous insanity case happened in 1843, with the McNaughton case. Englishman Daniel McNaughton shot and killed the secretary of the British Prime Minister, believing that the Prime Minister was conspiring against him. The court acquitted McNaughton "by reason of insanity," afterwards McNaughton spent the rest of his life incarcerated. .
The case caused such a public uproar that Queen Victoria ordered the court to develop a stricter test for insanity. Thus, the "McNaughton rule" was born which became the standard." Juries applied this after hearing medical testimony from prosecution and defense experts. The McNaughton rule created a presumption of sanity. Unless the defense proved that at the time of committing the act, the accused was laboring under such a defect of reason caused from disease of the mind so as not to know the nature and quality of the act he was doing or, if he did know it that he did not know what he was doing was wrong. The McNaughton rule became the standard for insanity in the United States and the United Kingdom (Bennett p. 46). After several tries at revising and improving the insanity defense, they found that the McNaughton rule was most efficient and is still in effect today. .
Most people are familiar with the insanity defense because of high profile cases, like that of John Hinckley Jr. who tried to assassinate Ronald Reagan to gain the love of the actor Jodi Foster. Of course, there are also the movies that come out of Hollywood like Psycho. "Few psycholegal issues are more controversial then the insanity defense. Although there are clear differences among individuals, the public generally has a negative opinion of the insanity defense that varies only in its intensity over time. Such opinions may have detrimental effects on a juror's ability to render an unbiased verdict (Galietta p.
