Diminished Responsibility

Key Facts:

• outlined in s52 Coroners and Justice Act 2009, replacing old law under the Homicide Act 1957
• Partial defence only available to murder- if it succeds, murder is reduced to voluntary manlsaughter
• DR must be proved on a balance of probabilities, by the party raising the defence (usually the D)

• s52(1) - a person (D) who kills or is a party to the killing of another is not to be convicted of murder if D was suffering from:
  • an abnormality of mental functioning [AoMF], which:
    • a) arose from a recognised medical condition
    • b) substantially impaired D's ability to
      • understand the nature and quality of his conduct and/or
      • form a rational judgement, and/or
      • exercise self-control and
    • c) provides an explanation for D's acts and omissions in doing, or being party to, the killing.

• For the jury to decide if D was suffering from an AoMF after hearing medical evidence

Byrne (1960)

• D = sexual psychopath
• killed woman
• Medical evidence: he could not control his perverted desires to kill
• Defence successful
  • CA defined AoMF: D's mental functioning was so different from that of ordinary human beings that the reasonable man would term it abnormal
  • AoMF includes inability to exercise will power and control

• Depression - Seers, Gittens
• Jealousy/Othello syndrome - Vinagre
• Paranoia
• Battered-woman syndrome - Duffy, Ahluwalia, Thornton
• Uncontrollable urges - Byrne
• Epilepsy - Campbell
• Sleep disorders
• Pre-menstrual tension - Smith, Reynolds
• Mental deficiency - Speuk
• Psychopathy - Byrne
• Alcoholism - see later cases

In determining what constitues a recognised medical condition, existing medically accepted classifications of abnormality will be used

The AoMF must have substantially impaired D's ability to do one or more of these three things:

• understand the nature of D's [own] conduct
• form a rationable judgement
• exercise self-control

Definition of 'substantially impaired':

• Egan, Thornton - 'substantial impairment' = 'need not mean total, but must be more than trivial'

Foye (2013)

• D = prisoner who killed another prisoner (a sex offender). Charged w/murder and raised DR
• not doubted that he had an AoMF, but question was whether that substntially impaired him?
• P had evidence that he was calm + in control, planned what he did + targetted V for being a sex offender
• Held: Defence failed - D's AoMF had not substantially impaired his ability to control himself

• AoMF must provide an explanation for D's acts and omissions
  • this will be if abnormality causes, or was at least a significant contributory factor in causing, the D to carry out the killing
    • Ministry of Justice Circular 2010/13 - "It [the abnormality] need not have been the only cause, the main cause or even the most important factor, but it must be more than merely trivial"

In cases where D was intoxicated, the jury must decide whether his responsibility would still have been impaired if he had been sober.

There are two situations where this might arise

• 1) D has an AoMF and is intoxicated
• 2) D's long term substance abuse -> alcohol/drug dependancy syndrome (a recognised medical condition) which causes an AoMF

jury should disregard intoxication and consider if AoMF on its own substantially impaired D's ability.

Egan (1992)

• D = mentally abnormal
• one day, he got drunk and bludgened an old lady to death
• CA: jury should disregard the intocication and only consider wheter the abnormality of mind was enough by itself that it amounted to DR

Dietschmann (2003)

• Lord Hutton: "has D satisfied you that, despite the drink, his mental abnormality substantially impaireed his mental responsibility for his fatal acts, or has he failed to satisfy you of that

Wood (2008)

• D (a chronic alcoholic) gruesomely killed V, while drunk
• CA: appeal allowed
  • Jury must consider whether D's syndrome (alcoholism) constituted an AoMF. If it was, they must consider whether this substantially impaired D's mental responsibility

Dowds (2012)

• D killed his partner (V) while intoxicated.
• D did not have alchohol dependence syndrome and had control over his drinking, but was a habitual binge drinker
• Trial judge: voluntary and temporary drunkness was not DR
  • D appealed, arguing that 'acute intoxication' is a desease and so satisfies a recognised medical condition
• Appeal dismissed. Voluntary acute intoxication, whether from alcohol or another substance, will not suffice DR
  • The appeal was dismissed, despite 'acute intoxication' being a recognised medical condition

• DR is outlined under s52 Coroners and Justice Act
• DR must be proved on a balance of probabilities by the party raising the defence (the D)
• s52 - a person (D) who kills, or is party to the killing is not to be convicted of murder if
  • D suffered an abnormality of mental functioning (Byrne), which
    • s52(1)(a) - arose from a recognised medical condition
    • s52(1)(b) - substantially impaired (meaning not 'tota'l, but 'more than trivial' - Egan, Thornton) his ability (Foye) to
      • understand the nature and quality of D's [own] acts and/or
      • form a reasonable judgement and/or
      • exercise self-control and
    • s52(1)(c) provides and explanation for D's acts
• In relation to diminished responsibility and intoxication:
• D may be intoxicated and suffer an abnormality of mental functioning, where the jury should disregard the intoxication and decide if the AoMF, on its own, was enough to substantially impair D (Egan, Dietschmann)
• D's long term substance abuse has led to dependency syndrome (Woods)
  • an AoMF cannot come from 'acute intoxication' (Dowds)