The principle of diminished responsibility in Ireland & Defence of Insanity

Diminished responsibility, since its inception, has been criticised extensively due to the underlying theoretical principles as well as the practical issues relating to its operation. Griew (1986) has referred to the doctrine as 'elliptical almost to the point of nonsense' while Gordon (2000) in his reflection of the doctrine in Scotland has referred to it as 'inaccurate' and Wootton (1960) as 'illogical.' The principle essentially acts as a partial defence in homicide cases in that it reduces a conviction of murder to one of manslaughter. In practice, the defence of diminished responsibility has been perceived as malleable, interpreted by socio-political issues rather than academic agreement. There is a seminal relationship between the principle of diminished responsibility and the defence of insanity as it acts as a means of mitigating the harsh effect of the mandatory life sentence for murder. The verdicts of diminished responsibility is therefore available when someone does not meet the test for a not guilty verdict by reason of insanity but still was suffering from a mental disorder which substantially decreased their responsibility for the killing.

The position in the United Kingdom

In 2003, debate intensified in the UK in the context of cases of domestic violence and murder and the partial defences which resulted in the Law Commission's Report on Partial Defences to Murder in 2003, which fundamentally reflected on the categorisation of homicide offences and the degree of seriousness associated to each offence. The report recommended two 'degrees' of homicide, first degree murder and second degree murder, with the principle of diminished responsibility being used to reduce offence from 1st degree to 2nd degree murder. In terms of the definition of diminished responsibility, the report states that it requires clarification and modernisation aligned with current diagnostic practices. Section 52(1) of the Coroners and Justice Act [2009] in England and Wales deals with the definition of diminished responsibility, which replaces the section 2(1) of the Homicide Act [1957]. The reason for this was that the 1957 facilitated a broad interpretation of the doctrine by the courts which was described by medical and legal professionals as a 'benign conspiracy' in cases where mental condition of an accused was not recognised as a mental disorder or medical condition. It still remains to be established the impact of section 52 in practice whether it will have any bearing on the particular offenders who would have been convicted of murder rather than manslaughter under the 1957 Act, as the 2009 Act does not refer to link to the special verdict under the M'Naghten rules, being that the accused did not understand what he did or failed to distinguish from right or wrong, due to a 'disease of the mind.' The Law Commission [2008] has stated concern that 'there is a need to reconsider the relationship between.... diminished responsibility and insanity.'

The position in Ireland

In the Irish criminal law, there exists three forms of insanity, firstly, the insanity defence under section 5, to seek an exception from criminal liability based on the absence of mens rea. Secondly, the defence of diminished responsibility under section 6 which reduces a murder charge to one of manslaughter. Thirdly, the unfit to be tried plea under section 4 of the Criminal Law (Insanity) Act [2006], being the main piece of legislation governing the principle of diminished responsibility and the defence of insanity in Ireland.

Prior to this was the Infanticide Act [1949] which asked the jury to return a verdict of infanticide in lieu of murder, the punishment the same as manslaughter. Throughout the 20th century, attempts were made to recognise the doctrine of diminished responsibility in the Irish common law, with none of them being successful. The first case which explored a reduced sentence for a murder conviction based on the absence of 'mental abnormality' was in the case of AG v O'Shea [1931] where the jury convicted the accused of manslaughter, rather than murder, due to the fact that the murder was committed during a period of mental abnormality. The case of Doyle v Wicklow County Council [1974] is also relevant in the development of diminished responsibility in the case law, as a volitional insanity test was approved of which worked to question the mental illness and impact of same on the actions of the accused which was used in addition to the M'Naghten rules under the ambit of insanity.

The 1980s brought a more overt approach to the question of diminished responsibility in Irish case law and the case of DPP v O'Mahony [1985] is of interest. In this case, the accused was charged with murder and during trial the defence counsel argued that his mental capability was impaired which impacted his responsibility for the acts committed. Jury was faced with question of convicting accused of murder, or of manslaughter on the facts presented. On appeal, it was held that a defence of diminished responsibility at common law and that the courts should consider to expand on this. Finaly CJ argued here that the Homicide Act [1957] was introduced to liberalise the rigidity of the M'Naghten rules. As a result, the decision in the case created an opportunity to introduce the concept of diminished responsibility by means of judicial activism (Kennefick, 2011).

The implementation of the Criminal Justice (Insanity) Act [2006] "gave legal standing to the partial defence of diminished responsibility in Irish law," with Section 6 provides that:

Where a person is tried for murder and the jury or, as the case may be, the Special Criminal Court finds that the person... b) was at the time suffering from a mental disorder...

Mental disorder is defined as (section 1) 'mental illness, mental disability, dementia, or any disease of the mind but does not include intoxication.' The judicial interpretation of section 6 has raised two important questions for the purposes of the defence of insanity and diminished responsibility, being 1. the notion of what accounts to mental disorder and 2. the question of causation, for example, is mental illness used as a sole or secondary cause to the offence committed by the accused? Since the inception of the Act, most cases utilising the defence of insanity have heavily relied on psychiatric medical evidence. The case of DPP v John Collins [2007], involved the clashing of two psychiatric professionals on the very definition of a mental disorder and could not agree on this. The definition of mental disorder is unclear in the Act if it extends to personality orders. This was later rejected based on fear that the defence would become a license to kill. With this being said, it can still be argued that a variety of personality disorders, such as psychopathy, may also be defined as a 'disease of the mind' as suggested it the case of DPP v O'Mahony. Kelly (2012) notes how 'the term is outdated and misleading, as the law is not primarily concerned with whether the mind was diseased, but rather with impairment of mental faculties and a risk or reoccurrence.'

The case of DPP v O'Dwyer is instructive in understanding the extent to which mental disorder may diminish responsibility of the accused to bring a successful defence. The case involved the defendant who brutally killed his teenaged sister in motiveless circumstances. Defence counsel argued that the defendant was suffering from temporal lobe epilepsy and depersonality disorder, however the medical professionals for the prosecution disagreed that the accused was suffering from depersonality disorder but rather was overcome with 'profound feelings of shame and embarrassment' following the fact that he was excessively drunk that weekend. In their decision, the jury accepted that the accused was in fact suffering from a condition amounting to a mental disorder which resulted in a substantial diminishing of the accused responsibility for the killing. Kennefick (2011) argues that this perhaps resulted from an 'underlying sense of humanity over strict legal principle... reminiscent of the early origins of the diminished responsibility doctrine which emerged from the Scottish jurisdiction.' However, what is evidenced in the case is that the establishment of a mental disorder was a significant contributory factor in diminishing responsibility, rather than it being the sole factor in the case, in line with Section 52 of the Coroners and Justice Act [2009].

Four cases of importance

M.C v Clinical Director Central Mental Hospital [2016], here an accused was found guilty but insane and was later re-classified as 'not guilty by reason of insanity' as per the Criminal Law (Insanity) Act [2006]

DPP v Ramzan [2016] - in this case during a trial for a drugs offence, the accused applied for the inclusion of expert evidence to support a plea of not guilty by reason of insanity. The trial judge refused his application on the grounds that the relevant legislation states that an expert of this type should be conducted by a consultant psychiatrist. The three witnesses were not consultant psychiatrist and the fourth was based in the UK and not registered in Ireland (which is a requirement of the Act). Defendant appealed this decision, upon which the court held that the UK psychiatrist would have been an appropriate witness to call. In his report, the witness stated ‘He says he knew what he was doing and what he was doing was wrong but went along with it as he was afraid.’ The fact that the accused had admitted to the psychiatrist that he understood the nature and quality of the act, and that he knew it was wrong, meant that the evidence from the psychiatrist in question would fall outside the statutory definition of insanity.

DPP v Heffernan [2015] - this case further confirmed that the onus to establish diminished responsibility on the balance of probabilities rests with the accused. In the case, the judge directed the jury that the accused had the burden of proof in this respect and that the standard was the balance of probabilities. On appeal, the defendant submitted that the burden of proof remained on the prosecution at all times and that the standard of proof was beyond a reasonable doubt. The Court of Appeal however, dismissed the application, stating that the 2006 Act is very clear in that it created a 'special verdict', subject to pre-existing common law rules as to the burden of proof in defences of insanity.

DPP v Tomkins [2012], defendant accused of murder sought to utilise the defence of diminished responsibility alongside the defence of provocation. The trial judge indicated in the case that the premeditation was inconsistent with a defence of provocation, but failed to direct the jury that it was not necessarily inconsistent with diminished responsibility. Though not raised by the defence at trial, the Court of Appeal held that the jury were likely to be left with an 'incomplete and erroneous view of the law' and as such, the conviction was quashed and a re-trial was directed.

Concluding thoughts

Proposals for the reform of the criminal law concerning defence of insanity has been debated and criticised in Ireland for decades. Factors within the proposals consisted of traditionally low rates of crime and imprisonment in Ireland and the absence of public activism about the crime, until the 1960s. The Criminal Law (Insanity) Act [2006] responding to these issues, attempting to extinguish the problems of the law in this area, specifically procedural issues. Many scholars have called for the defence of insanity to be abolished due to the absence of mens rea, or at the very least to be abolished as a separate defence however, this being said, it is widely accepted by many professionals and academics as a vital element of the criminal law in order to secure the functioning of the criminal justice system.