Diminished Responsibility
Definition
A partial defence that reduces murder to manslaughter in the UK (Homicide Act 1957 § 2 as amended by Coroners and Justice Act 2009 § 52), requiring a recognised medical condition that substantially impairs responsibility. Neuropsychological evidence may support this defence.
- Legal status
- Partial defence (UK, Scotland) or sentencing mitigation (Germany, India)
- Outcome when accepted
- Murder reduced to manslaughter (UK/Scotland) or sentence reduction (Germany/India)
- Key requirement
- Recognised medical condition that substantially impaired responsibility
Common questions
How is diminished responsibility different from the insanity defence?+
Insanity fully acquits a defendant of criminal responsibility. Diminished responsibility is a partial defence where the defendant's mental condition substantially impairs but does not eliminate responsibility. It reduces the charge or sentence rather than removing it entirely.
What happens when diminished responsibility is accepted as a defence?+
In the UK and Scotland, a murder conviction is reduced to manslaughter, which carries a lower sentence. In Germany and India, it reduces the sentence imposed. The defendant is still convicted but faces a lesser penalty because their mental abnormality substantially impaired their responsibility.
What kinds of evidence support a diminished responsibility claim?+
Neuropsychological evidence can support the defence. The defendant must show they had a recognised medical condition that substantially impaired their responsibility at the time of the offence.
Related terms
- Miller V. Alabama (2012)
- US Supreme Court ruling prohibiting mandatory life-without-parole sentences for offenders who were under 18 at the time of their offence, on the...
- Roper V. Simmons (2005)
- US Supreme Court decision prohibiting capital punishment for offenders who were under 18 at the time of their crime, resting in part...
- Atkins V. Virginia (2002)
- US Supreme Court ruling categorically prohibiting the execution of intellectually disabled defendants under the Eighth Amendment; Hall v. Florida (2014) and Moore...
- Battered-Woman Syndrome (BWS)
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- BNS § 22
- India's insanity defence provision in the Bharatiya Nyaya Sanhita 2023, replacing IPC § 84: an act is not an offence if done...
- BSA § 39
- Section 39 of the Bharatiya Sakshya Adhiniyam 2023 (formerly IEA § 45), governing the admissibility of expert opinion in Indian courts. The...
- CJA 2009 § 52
- Coroners and Justice Act 2009 § 52, amending Homicide Act 1957 § 2: the defendant must show an abnormality of mental functioning...
- Foetal Alcohol Spectrum Disorder (FASD)
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- Lockett V. Ohio (1978)
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- MacArthur Law and Neuroscience Project
- A MacArthur Foundation-funded research network (2007-2017) producing the leading academic framework for integrating neuroscience into criminal law, distinguishing group-level findings from individual-level...
- Neurolaw
- The interdisciplinary field at the intersection of neuroscience and criminal law, addressing how brain science can and should inform legal concepts of...
- Prefrontal Cortex (PFC)
- The frontal brain region responsible for impulse control, planning, and decision-making. Reduced grey matter volume and lower activation in the PFC have...
Explained in these topics
- Diminished Responsibility and MitigationA partial-responsibility doctrine that reduces a murder conviction to manslaughter (UK, Scotland) or reduces sentence (Germany, India) where the defendant's me...
- Neurolaw: Frontal-Lobe Evidence and Criminal ResponsibilityA partial defence that reduces murder to manslaughter in the UK (Homicide Act 1957 § 2 as amended by Coroners and Justice Act 2009 § 52), requiring a recognise...