New South Wales Consolidated Acts

CRIMES ACT 1900 - SECT 23A

23A Substantial impairment by abnormality of mind

(1) A person who would otherwise be guilty of murder is not to be convicted of murder if:

(a) at the time of the acts or omissions causing the death concerned, the person’s capacity to understand events, or to judge whether the person’s actions were right or wrong, or to control himself or herself, was substantially impaired by an abnormality of mind arising from an underlying condition, and

(b) the impairment was so substantial as to warrant liability for murder being reduced to manslaughter.

(2) For the purposes of subsection (1) (b), evidence of an opinion that an impairment was so substantial as to warrant liability for murder being reduced to manslaughter is not admissible.

(3) If a person was intoxicated at the time of the acts or omissions causing the death concerned, and the intoxication was self-induced intoxication (within the meaning of section 428A), the effects of that self-induced intoxication are to be disregarded for the purpose of determining whether the person is not liable to be convicted of murder by virtue of this section.

(4) The onus is on the person accused to prove that he or she is not liable to be convicted of murder by virtue of this section.

(5) A person who but for this section would be liable, whether as principal or accessory, to be convicted of murder is to be convicted of manslaughter instead.

(6) The fact that a person is not liable to be convicted of murder in respect of a death by virtue of this section does not affect the question of whether any other person is liable to be convicted of murder in respect of that death.

(7) If, on the trial of a person for murder, the person contends:

(a) that the person is entitled to be acquitted on the ground that the person was mentally ill at the time of the acts or omissions causing the death concerned, or

(b) that the person is not liable to be convicted of murder by virtue of this section,

evidence may be offered by the prosecution tending to prove the other of those contentions, and the Court may give directions as to the stage of the proceedings at which that evidence may be offered.

(8) In this section:
"underlying condition" means a pre-existing mental or physiological condition, other than a condition of a transitory kind.