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The Defence of Insanity (Qld)


Under the Queensland Criminal Code 1899, if an accused person was unable to comprehend or govern their actions due to a mental illness or disability at the time of an alleged criminal act, they have a complete legal defence against any criminal charges. This defence is set out in section 27 of the Criminal Code 1899. This page deals with the defence of insanity in Queensland.

When does the defence of insanity apply?

Section 27 of the Criminal Code 1899 states that a person cannot be held responsible for a criminal act or omission if they were affected by a mental disease or infirmity that rendered them incapable of controlling their actions, comprehending their actions, or understanding that they ought not to do the actions.

A mental disease or infirmity is a condition that impacts the functions of the mind, such as the ability to reason or recall. This can include mental illnesses, brain damage, intellectual disabilities, or even temporary mental disorders like a concussion.

The Queensland Mental health Court

The Mental Health Court is responsible for deciding the cases of individuals who are facing serious charges on indictment and are using the defence of insanity. This court is composed of a Supreme Court judge and two clinicians.

If a person is facing charges in the Magistrates Court or Children’s Court and is raising the defence of insanity, their case will remain before a magistrate.

Burden of proof

In cases where the defence of insanity is raised, the burden of proof lies with the accused to convince the court that they were not mentally sound at the time of the alleged offence. The accused must prove this on the balance of probabilities.

In order to establish that the defence of insanity applies, the accused must demonstrate that they were suffering from a mental disease or infirmity at the time of the alleged offense. Furthermore, they must prove that this condition made it impossible for them to control or comprehend their actions, or to recognize that their actions would be viewed as wrong by the community.

Defence of insanity and expert evidence

In cases where the defence of insanity is being advanced, both the defence and prosecution may introduce expert evidence to support their respective positions. Expert witnesses may provide testimony regarding whether the accused was insane at the time of the alleged offence.

The ultimate decision as to whether the defence of insanity succeed is made by the court based on all of the evidence presented. The opinions of expert witnesses are not conclusive and do not guarantee a particular outcome. In cases that are being decided by a jury, the jury is not required to accept the expert evidence that is presented.

Qualified acquittal

When a person is acquitted of an offence on the grounds of insanity, this is referred to as a qualified acquittal. In such cases, the individual will be dealt with under the Mental Health Act 2016.

Under this act, an individual who has been found not guilty by reason of insanity may be subject to either a Forensic Order or a Treatment Support Order. A Forensic Order is typically imposed when the court deems it necessary to protect the community from the risk of significant harm. In such cases, the individual may be involuntarily subjected to treatment and care and detained in an authorized mental health or Forensic Disability Service facility. The order is regularly reviewed by the Mental Health Court.

Alternatively, a Treatment Support Order may be imposed when a Forensic Order is not deemed necessary to protect the community. In such cases, the individual typically resides in the community, unless there is a compelling reason for them to receive inpatient care.

Fitness for trial

In some cases where the defence of insanity is at issue, the accused’s fitness for trial may also be at issue. However, these two issues are separate.

A person’s fitness to plead depends on their mental capacity at the time the matter comes to court. If the accused is not able to comprehend the proceedings, enter a plea, instruct their lawyer and endure the proceedings without significant mental harm, they are not fit for trial. This means that the proceedings cannot continue unless or until the person has become fit for trial.

In contrast, the defence of insanity hinges on the accused person’s mental capacity at the time of the alleged offence.

If you require legal advice or representation in any legal matter, please contact Armstrong Legal.

Fernanda Dahlstrom

This article was written by Fernanda Dahlstrom

Fernanda Dahlstrom has a Bachelor of Laws, a Bachelor of Arts and a Graduate Diploma in Legal Practice. She has also completed a Master’s in Writing and Literature. Fernanda practised law for eight years, working in criminal defence, child protection and domestic violence law in the Northern Territory and in family law in Queensland.

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