Mental impairment and intellectual disability as a sentencing factor
A court must take into account an offender’s mental health or intellectual functioning, whether resulting from illness, injury, disability, or disorder, whether permanent or temporary, mild or severe, and whether it existed at the time of offending or sentencing or both.
In Victoria, ‘impaired mental functioning’ is defined in the Sentencing Act 1991 s 10A to include a mental illness, intellectual disability, an acquired brain injury, autism spectrum disorder or neurological impairment, including but not limited to dementia.
However, the question is not about diagnostic labels but specifically how the condition affected an offender at the time of offending and how it is likely to impact their experience of imprisonment (Verdins at , Leeder at , Carroll at ).
Following the case of R v Verdins & Ors  VSCA 102 (Verdins), it is an accepted legal principle that psychiatric illness or impaired mental functioning, whether temporary or permanent, is a relevant sentencing consideration and may reduce the moral culpability of an offender and affect the appropriateness of imprisonment as a vehicle for general deterrence. Intellectual disability has specific cases that tie into the principles established in Verdins.
In the case of Verdins, the Court of Appeal stated that impaired mental functioning, whether temporary or permanent, is relevant to sentencing in at least six ways:
It may reduce the offender’s moral culpability for the offending. Where that is so, the impairment affects what is considered to be a just punishment and lessens the need for denunciation as a relevant sentencing consideration.
It may have a bearing on the type of sentence that is imposed and the conditions in which the sentence should be served.
General deterrence may be moderated or eliminated as a sentencing consideration. This depends on the nature and severity of the offender’s symptoms and the effect of the impairment at the time of offending, sentence, or both.
Similarly, specific deterrence may be moderated or eliminated as a sentencing consideration depending on the nature and severity of the offender’s symptoms.
The existence of the impairment at the time of sentencing (or its foreseeable recurrence) may mean that a particular sentence weighs more heavily on the offender than it would on a person of normal health.
Where there is a serious risk of imprisonment having a significant adverse effect on the offender’s mental health, this will be a factor tending to mitigate punishment (Verdins at ).
The Verdins principles, if invoked, may moderate both the minimum term and the head sentence (R v Vuadreu at ).
Case law on intellectual disability during sentencing
Specific case law highlights the relevant sentencing considerations applying to intellectual disability.
In Leeder, both sitting Judges enlivened the issue of intellectual disability as a relevant sentencing consideration.
In delivering his judgment, Justice Maxwell spoke of the need to consider intellectual disabilities as an important sentencing consideration, just as mental impairment has been addressed by the principles set out in Verdins. His Honour stated that:
It seems to me important to ensure that this species of mental impairment is addressed with the same rigour and specificity as necessary in relation to the more familiar area of mental illness.
Similarly, Justice Buchannan opined when sentencing an offender who was deemed to have an IQ of 67:
It is, I think, unfortunate that there are no more appropriate methods than imprisonment for dealing with intellectually handicapped offenders, who are subject to forces with which they are ill equipped to deal. Imprisonment is a blunt instrument, which is not designed to deal with the appellant.
The case also raised issues concerning what equates to a ‘mild’ versus ‘severe’ intellectual disability, as there has been a disparity in recent case law (see DPP v Lovett in which the respondent was described as being severely intellectually disabled and had an IQ of 70, slightly higher than the appellant in Leeder). Regarding this the disparity, Justice Maxwell stated:
The use of labels such as ‘mild’ or ‘moderate’ or ‘severe’ intellectual disability does not assist the sentencing court in deciding whether, and if so to what extent, sentencing considerations are affected by the condition of the particular person. What the Court needs to know is how the disability (is likely to have) affected the mental functioning of the particular offender at the time of the offending (or in the lead-up to it) and/or how it is likely to affect him/her in the future. As with mental illness, so with intellectual disability, there is scope for considerable refinement of expert opinion, and therefore of argument before sentencing courts, about how these matters are to be taken into account.
Both Justices agreed that ‘as with mental illness, so with intellectual disability, there is scope for considerable refinement of expert opinion, and therefore of argument before sentencing courts, about how these matters are to be taken into account’ .
In the more recent case of Muldrock v R, the High Court reiterated to some degree the findings in Leeder. In that case, the appellant had been sentenced for a sexual offence against a minor. Expert evidence was that the appellant had an IQ score of 62, as a result of which the appellant functioned at a level lower than 99 per cent of the population. Psychological evidence suggested that the appellant’s retarded development was the cause of his difficulty in managing his impulses and controlling his actions.
The High Court observed that one of the purposes of sentencing is to deter others who might be minded to offend as the offender has done (at [ 53]). The court cited a passage in which Young CJ said:
General deterrence should often be given very little weight in the case of an offender suffering from a mental disorder or abnormality because such an offender is not an appropriate medium for making an example to others.
In that same case, Lush J explained the reason for the principle in the following way:
[The] significance [of general deterrence] in a particular case will, however, at least usually be related to the kindred concept of retribution or punishment in which is involved an element of instinctive appreciation of the appropriateness of the sentence to the case. A sentence imposed with deterrence in view will not be acceptable if its retributive effect on the offender is felt to be inappropriate to his situation and to the needs of the community.
In Muldrock, the High Court (at ) continued that:
[The principle] applies in sentencing offenders suffering from mental illness, and those with an intellectual handicap. A question will often arise as to the causal relation, if any, between an offender’s mental illness and the commission of the offence. Such a question is less likely to arise in sentencing a mentally retarded offender because the lack of capacity to reason, as an ordinary person might, as to the wrongfulness of the conduct will, in most cases, substantially lessen the offender’s moral culpability for the offence. The retributive effect and denunciatory aspect of a sentence that is appropriate to a person of ordinary capacity will often be inappropriate to the situation of a mentally retarded offender and to the needs of the community.
The High Court held that the appellant’s superficial understanding that it was wrong to engage in the offending conduct and that he told childish lies to shift blame from himself were not reasons to assess the criminality of his conduct as significant and did not justify using him as a medium by which to deter others from offending (at ).
Mental health during sentencing
A relationship between a mental illness and the commission of an offence will not always result in a reduced sentence. This concept was highlighted in the case of Veen v The Queen (No 2) (1988) 164 CLR 465, in which the majority found that a mental condition that makes an offender a danger to society when at large but which diminishes moral culpability for a crime has ‘two countervailing effects: one which tends towards a longer custodial sentence, the other towards a shorter’.
In R v Engert (1996) 84 A Crim R 67, Gleeson CJ described the effects at 71:
‘the existence of a causal connection between the mental disorder and the offence might reduce the importance of general deterrence, and increase the importance of particular deterrence or of the need to protect the public.’
In Director of Public Prosecutions (Cth) v De La Rosa at , it was identified that where a person has been diagnosed with an antisocial personality disorder, there may be a particular need to give consideration to the protection of the public (citing R v Lawrence (2005) NSWCCA 91 at ).
For example, in R v Adams  NSWCCA 448, there was evidence before the Court that the offender had a personality disorder with borderline and antisocial features. In the case, it was held that the psychiatric evidence did not support substantial impairment of the offender’s capacity to understand events or to judge whether her actions were right or wrong. However, it was accepted to indicate that the offender’s capacity to control herself was substantially impaired.
In Payne v The Queen, the applicant, a former military officer, sought to appeal against sentence following a guilty plea to four charges related to extortion of a casino. The applicant was diagnosed with major depressive disorder and had experienced a manic episode, which was said to have led to his planning and scheming of the offence.
The court considered the high degree of criminality engaged in by the applicant, the meticulous and skilful planning over an appreciable period, the use of highly effective guerrilla tactics, the high degree of disruption caused to the community and the business entity, and the ruthlessness displayed by the applicant. The court also considered the psychiatric and psychological evidence presented, which may have impaired his judgment; however, the court dismissed the appeal and upheld the sentence of 12 years’ imprisonment.
The appellant in Astbury v The Queen, had a history marked by serious and long-standing mental impairment and had been diagnosed with schizoaffective disorder. The appellant was initially convicted of murder for the death of a victim caused by severe blunt-force trauma to the chest. The appellant appealed the conviction, which was upheld, and the verdict for murder was quashed and replaced with a conviction for manslaughter.
On resentencing for manslaughter, the court accepted that the appellant’s mental health condition rendered him confused and agitated and unable to think in a clear and coherent manner, nor was he able to inhibit his impulses at the time of offending.
The sentencing judge noted the primary judge’s findings that the sentencing purposes of general deterrence and specific deterrence were materially moderated. In addition, the court noted, as a consequence of the appellant’s mental impairment, the primary judge’s persuasion, to a limited degree, that he was likely to find a sentence of imprisonment more onerous than a person of normal health. The court resentenced the appellant to 9 years’ imprisonment with a non-parole period of 6 years.