Diminished Responsibility

Diminished Responsibility

1. Partial Defence to murder

2. Defined by Lord Parker as: "a state of mind so different from that of ordinary human beings that the reasonable man would determine it abnormal."

3. Homicide Act 1957 S2(1) amended by the Coroners and Justice Act 2009

4. A person who kills or is party to the killing of another is not to be convicted of murder if he was suffering from an abnormality of the mind that:

   • A) arose from a recognised medical condition
   • B) substantially impaired D's ability to:
     • understand the nature of his conduct
     • form a rational judgement
     • exercise self-control
   • provides an explanation for D's acts and omissions in doing or being party to the killing.

5. Abnormaility of mental functioning

   • S52 of the Coroners and Justice Act 2009 amended from 'abnormaility of the mind'.
   • Byrne: 'a state of mind so different from that of ordinary human beings that the reasonable man would term it abnormal.'
   • Cause of the abnormality of mental functioning
     • S2(1) of the Homicide Act, as amended, the cause must arise from a 'recognised medical condition'.
     • This is wide enough to cover physical and psychological.
       • It obviously therefore covers any recognised mental disorder.
         • This can be wide ranging such as depressive illness, paranoi or Battered Women's Syndrome.
       • It also covers any physical condition which affects mental functioning such as epilepsy, sleep disorders or diabetes.

6. Substantially impaired

   • The abnormality of mental functioning must substantially impair the D's mental responsibility for his acts or omissions in doing or being party to the killing.
   • In Byrne the C.O.A said that the question of whether the impairment was substantial was one of degree and that it was for the jury to decide.
   • In Lloyd it was held that substantial does not mean total, nor does it mean trivial or minimal.
   • As it is a question of fact, the judge may withdraw the point from the jury if there is no evidence on which a reasonable jury could conclude that the D's mental responsibility was substantially impaired.
   • The D's ability to do one of three things must be substantially impaired, these are set out in S2(1A) of the Homicide Act 1957.
     • to understand the nature of his conduct
       • This covers situations where the D is in an automatic state and does not know what he is doing.
       • It also covers situations where the D suffers from delusions and believes, for example that he is killing the devil when in fact he is killing a person. In this situation he does not understand the nature of what he is doing.
       • It could also cover people with severe learning difficulties whose mental age is so low that they do not understand the nature of what they are doing.
     • to form a rational judgement
       • Even if the D does know the nature of his conduct he may not be able to form a rational judgement about his acts or omissions.
       • Those suffering from paranoi or schizophrenia may well not be able to form a rational judgement.
       • Another recognised medical conditionwhere D may not be able to form a rational judgement is Battered Women's Syndrome.
     • to excersice self-control

7. Provides an explanation for D's conduct

   • This new principle was introduced by the Coroners and Justice Act 2009
   • There must now be some casual connection between D's abnormailty of mental functioning and the killing.
   • S2(1B) of the Homicide Act 1957 explains this further as it states: "an abnormality of mental functioning provides an explanation for D's conduct if it causes or is a significant contributory factor in causeing, D to carry out that conduct."