The Defence of Mental Impairment (ACT)

In the ACT, a person who is charged with offences can rely on the defence of mental impairment. This defence is contained in sections 28 and 29 of the Criminal Code 2002. Mental impairment provides a full defence to any criminal charge because of the principle that no one should not be held criminally responsible for conduct they carried out when they were unable to understand or control their actions. This page outlines the defence of mental impairment in the ACT.

Mental impairment vs unfitness to plead

The question of whether a person is not guilty based on mental impairment is separate from the question of whether they are unfit to plead; however, both issues often arise in the same case.

The defence of mental impairment relates to whether the accused person was capable of understanding and controlling their actions at the time of the alleged offence. Their state of mind at the time of the trial is not at issue.

Conversely, fitness to plead concerns whether the accused person is capable of understanding and participating in the court proceedings. Their state of mind at the time of the alleged offence is not relevant.

What is mental impairment?

Under section 27 of the Criminal Code 2002, mental impairment encompasses both short-term and long-term mental illnesses, intellectual disability, senility, brain damage and severe personality disorders.

The defence of mental impairment in the ACT

A person is not criminally responsible for an offence if, at the time of carrying out the acts making up the physical element of the offence, they were suffering a mental impairment that caused them:

• not to know the nature or quality of their conduct;
• not to know that the conduct was wrong;
• not to be able to control their conduct.

This is set out in section 28 of the Criminal Code.

What is the standard of proof?

A person is presumed to be of sound mind until proven otherwise. This presumption is displaced if the court is satisfied that on the balance of probabilities the person was suffering from a mental impairment, which had the effect described in section 28 of the Criminal Code.

Expert evidence

When the defence of mental impairment is raised, the court will usually hear evidence from psychiatrists and/or psychologists. Expert witnesses may give evidence as to whether the accused was mentally impaired at the time of the alleged offence. However, the court will decide whether the accused is not guilty based on mental impairment based on all the evidence and on a consideration of all the circumstances surrounding the alleged acts. It will not necessarily accept the opinions of the expert witnesses.

Where person found not guilty because of mental impairment

If an accused person has been found to have committed the physical elements of an offence but is not guilty based on mental impairment, this does not result in a full acquittal. The matter must then be referred to ACAT so that the accused can be assessed under the Mental Health Act.

ACAT may then make one of the following orders.

Psychiatric Treatment Orders

Under section 59 of the Mental Health Act, a psychiatric treatment order (PTO) can be made where a person:

• Has a mental illness;
• Cannot, or does not, consent to treatment, care or support;
• Is doing or is likely to do serious harm to themselves or someone else;
• Is suffering, or is likely to suffer, serious mental or physical deterioration.

A PTO authorises a person’s involuntary treatment in a mental health facility. It may also impose restrictions on their communication with others.

Community Care Order

Under section 66 of the Mental Health Act, a community care order (CCO) can be made where a person:

• Has a mental disorder;
• Cannot, or does not, consent to treatment, care or support;
• Is doing or is likely to do serious harm to themselves or to someone else;
• Is suffering, or is likely to suffer, serious mental or physical deterioration.

A CCO can authorise a person’s involuntary treatment, care and support in a mental health facility or in the community. It can also impose restrictions on their freedom.

A thorough consultation process must occur before making a PTO or CCO because both orders involve restrictive practices and involuntary treatment.

If you require legal advice or representation in any legal matter, please contact Go To Court Lawyers.