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Supreme Court 11 August 2026

R v Davidson

[2026] NSWSC 958

Homicide

Citation: R v Davidson [2026] NSWSC 958
Court: Supreme Court of New South Wales
Date: 11 August 2026
Judge(s): Campbell J

Background

The accused was charged with the murder of his mother at Gunnedah on 25 October 2024. The matter was listed for a judge-alone trial under s 132 of the Criminal Procedure Act 1986 (NSW). Following arraignment, both the prosecution and the accused, through counsel, agreed that the evidence established a defence of mental health impairment.

The accused had a history of ADHD and Asperger's Syndrome diagnosed from childhood. He had not been under any treatment regime at the time of the offence. Psychiatric assessments conducted after the offence found evidence of psychotic illness, including fixed delusions and significant paranoia that had been apparent in the period leading up to the killing.

The court was not required to determine a contested trial. Its task was to consider whether, as required by s 31 of the Mental Health and Cognitive Impairment Forensic Provisions Act 2020 (NSW) (the Act), the evidence independently satisfied the mental health impairment defence before entering a special verdict.

  • Whether the agreed evidence, including the expert psychiatric reports of Dr O'Dea and Dr Chew, was sufficient to satisfy the court that the mental health impairment defence under s 28 of the Act was established.
  • Specifically, whether the accused, at the time of the act, did not know that his act was wrong, in the sense that he could not reason with a moderate degree of sense and composure about whether the act, as perceived by reasonable people, was wrong.
  • What orders should follow a special verdict of act proven but not criminally responsible.

Decision

Issue 1: The statutory framework and the court's independent role

Campbell J emphasised that, even where both parties agree the evidence establishes the defence, the court must independently consider that evidence and be satisfied the defence is made out before entering a special verdict: s 31(c) of the Act. A special verdict carries legal consequences that are materially different from a plain acquittal. The accused does not walk free; rather, the court is empowered to order continued detention, and unconditional release is available only if the court is satisfied that the safety of the accused and the public will not be seriously endangered.

Issue 2: The mental health impairment defence

The defence under s 28 of the Act requires that, at the time of the act, the accused had a mental health impairment that meant he either did not know the nature and quality of the act, or did not know the act was wrong. Drawing on the longstanding authority in The King v Porter (1933) 55 CLR 182, Campbell J confirmed that "wrong" in this context means morally wrong by everyday standards, and that the relevant incapacity is the inability to reason about the wrongness of the act with a moderate degree of sense and composure. The expert evidence was uncontested that the accused knew the nature and quality of the act. The question turned solely on whether he knew the act was wrong.

Issue 3: Application of the evidence

Campbell J was satisfied, on the balance of probabilities and on the basis of the agreed facts and the psychiatric reports tendered as exhibits, that the accused's mental health impairment at the time of the offence meant he could not reason with a moderate degree of sense and composure about whether the act was wrong. The defence was therefore established, and the court returned a special verdict of act proven but not criminally responsible.

Orders Made

  • A special verdict of act proven but not criminally responsible was returned on the murder charge.
  • The accused is to be detained in a correctional facility, or at such other place as the Mental Health Review Tribunal may determine from time to time, until released by due process of law: s 33(1)(b) of the Act.
  • The accused was referred to the Mental Health Review Tribunal under s 34 of the Act.
  • The Registrar was directed to notify the Mental Health Review Tribunal and the Justice Health and Forensic Mental Health Network as soon as practicable, and to provide each body with the reasons for verdict and the exhibits tendered, including the agreed facts and the reports of Dr Chew and Dr O'Dea.

Key Takeaways

  • Under s 31 of the Mental Health and Cognitive Impairment Forensic Provisions Act 2020 (NSW), agreement between the parties that the evidence establishes a mental health impairment defence does not remove the court's obligation to independently consider that evidence and be satisfied the defence is made out before entering a special verdict.
  • A special verdict of act proven but not criminally responsible does not result in unconditional release. Campbell J noted that such an outcome would be appropriate almost never, and the court's power to order unconditional release is conditioned on satisfaction that the safety of the accused and the public will not be seriously endangered.
  • The test for not knowing an act is "wrong" under s 28(1)(b) is whether, by reason of mental health impairment, the accused could not reason with a moderate degree of sense and composure about whether the act, as perceived by reasonable people, was morally wrong, following The King v Porter (1933) 55 CLR 182.
  • Following a special verdict and an order for detention, the accused becomes a forensic patient under the supervision of the Mental Health Review Tribunal, which must review the matter at least every six months and cannot order release unless satisfied as to the safety of both the accused and the public.
  • Not every mental illness satisfies the criminal law defence of mental health impairment. As the judgment reaffirms, the criminal law standard is distinct from medical or civil law concepts of mental illness, and is directed specifically at whether the accused could reason about the wrongness of the particular act at the particular time.

Legislation and Cases Referenced

Legislation
- Criminal Procedure Act 1986 (NSW), s 132
- Mental Health and Cognitive Impairment Forensic Provisions Act 2020 (NSW), ss 28, 31, 33, 34

Cases
- Hawkins v the Queen (1994) 179 CLR 500; [1994] HCA 28
- R v Minani (2005) 63 NSWLR 490; [2005] NSWCCA 226
- The King v Porter (1933) 55 CLR 182; [1933] HCA 1