The M"Naughten rule was subsequently introduced and remains so, even today in Australian jurisdictions (with minor amendments).
"it must be clearly proved that, at the time of the committing of the act, the party accused was labouring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing; or if he did know, that he did not know that was he was doing was wrong" (Ten C.L, Crime Guilt and Punishment, 1990 pg 3) .
It seems ridiculous that a code formed 163 years ago is still being drawn upon in today's ever changing society. With the emergence of several medical and psychological breakthroughs regarding forensic/criminal psychology, the Queensland legal system is still using a rule formed when there was no access to diagnostic equipment and expert medical opinions, no previous precedents or access to statical data. This places a mentally ill defendant at a disadvantage from the start, having to prove their case without great importance being placed on various medical analytical equipment at their disposal. Rather than undertaking a series of psychological testing, the defence has to try to prove to the judge/jury that their client is in fact mentally ill based on a 163 year old ruling. Of course psychologists are consulted, and some testing may be done, but very little significance is placed on these outcomes rather it comes back to the M"Naughten ruling on whether or not the defendant was unaware of the act he was committing at the time. .
It is a great public misconception that the insanity defence is used regularly to "get off" lightly and obscure the Queensland Legal System. Wallace (1986) examined the prevalence of mental disorders among homicide offenders in NSW between 1976 and 1990 and found that in a fourteen year period only 2.8% of offenders in the study were found not guilty by reasons of insanity, although at least 16% of offenders were known to have some kind of mental disorder at the time.
