The history of the insanity defence has been well documented by historians. What follows is a very brief outline of the history of the insanity defence to provide some basic understanding of terms/events which may pop up in future posts.
Successful insanity defences have been made in the courtroom since at least 1505.[i] If a defendant was acquitted on the grounds of insanity at this time, he was free to go home. A legal landmark occurred in 1800 following the attempted assassination of King George III by ex-army officer James Hadfield, who was suffering from religious delusions. Hadfield believed that his death at the hands of the state (his crime being a capital offence) would cause the return of Jesus Christ.[ii] As the intended victim was the King, Hadfield was charged with treason and not with attempted murder, as would have been the case had he committed the offence against an ordinary citizen. A charge of treason meant that Hadfield had access to privileges not granted to other criminals, the most important of these were the requirement that the charge against him be proven by the testimony of two witnesses, instead of the one witness required in ordinary prosecutions, and access to a defence counsel.[iii] Only total insanity was deemed an acceptable reason for an acquittal. At Hadfield’s trial, however, his lawyer, the celebrated advocate Thomas Erskine, successfully managed to have him acquitted on the grounds of insanity based on the existence of his religious delusion. As historian Joel Eigen writes, ‘Delusion suggested a state of partial derangement – “total” to be sure when the subject of the delusory belief was touched upon – but absent when any other subject was invoked.’[iv] The verdict caused judicial concern. Legally, Hadfield could only be detained until he regained his sanity and it was feared that since he was not totally insane then he would be discharged during a lucid interval and pose a potential threat to society.[v] One month after Hadfield’s trial, The Criminal Lunatics Act (1800) was passed which empowered judges in cases of insanity acquittals to order the person to be detained until ‘His Majesty’s pleasure be known.’[vi]
A second legal landmark occurred in 1843 following the trial of Daniel McNaughton who had shot and killed Edward Drummond, private secretary to the British Prime Minister, Sir Robert Peel. McNaughton was under the delusion that he was being persecuted by the Tories, and he had meant to kill Peel. He was found ‘not guilty on the grounds of insanity’ and ordered to be detained until ‘Her Majesty’s pleasure be known.’ He was sent to Newgate Prison before his transfer to Broadmoor in 1864; he died the following year.[vii] The verdict was deemed too lenient by some and the Law Lords developed a set of rules for future cases. These became known as the McNaughton Rules and, amongst other things, they stated:
[To] establish a defence on the grounds of insanity, it must be clearly proven that at the time of committing the act, the party accused was labouring under such defect of reason, from disease of mind, 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 that what he was doing was wrong.[viii]
The Rules attempted to control the forms of insanity that were acceptable when invoking the insanity plea, and excluded the idea of ‘moral insanity’ (‘emotional insanity’) by which someone could be intellectually sane but suffer from derangement of the emotions. The Rules restricted inquiry to the cognitive capacity, thus insanity was not viewed as the inability to control the will. Furthermore, for a plea of insanity to be upheld, it had to be proven that the defendant suffered from delusions.[ix]