Mental Impairment (ACT)

The defence of mental impairment in the ACT is set out in sections 28 and 29 of the Criminal Code 2002. It provides a full defence to any criminal offence based on the principle that a person should not be held criminally responsible for acts that they did when they could not understand or control their actions. This page deals with the defence of mental impairment in the ACT.

Mental impairment vs unfitness to plead

Whether the defence of mental impairment applies in a criminal matter is a separate issue from the question of whether the accused is fit to plead; however, both issues may arise in the same case.

The defence of mental impairment relates to whether the accused had the requisite capacity to understand and control their actions at the time of the alleged offence. Their state of mind at the time the matter goes to trial is not at issue.

Conversely, fitness to plead concerns whether the accused has the requisite capacity to understand and participate in the court proceedings. Their state of mind at the time of the alleged offence is not relevant to their fitness to plead.

What is mental impairment?

Under section 27 of the Criminal Code 2002, mental impairment includes mental illness of both long and short duration, senility, intellectual disability, brain damage and severe personality disorder.

The defence of mental impairment

Under section 28 of the Criminal Code, a person is not criminally responsible for an offence if, at the time of carrying out the acts, they were suffering a mental impairment that had the effect that they:

• Did not know the nature or quality of their conduct;
• Did not know that the conduct was wrong;
• Could not control their conduct.

Standard of proof

A person is presumed to be of sound mind until the contrary is proven. Either the defence or prosecution can raise the issue of mental impairment during a trial. The presumption is displaced if it is proved on the balance of probabilities that the accused was suffering from a mental impairment and that it had the effect described in section 28.

Expert evidence

When the defence of mental impairment is raised, the court will usually hear evidence from one or more expert witnesses such as psychiatrists or psychologists. Expert witnesses may give evidence as to whether the accused was mentally impaired at the time of doing the alleged acts. However, the court is not obliged to accept the evidence given by experts.

Whether the accused is not guilty of the offence based on mental impairment is to be decided based on all the evidence before the court and with consideration to all the circumstances surrounding the alleged offence.

Where accused found not guilty because of mental impairment

If an accused person is found not guilty on the basis of mental impairment but the physical elements of the offence have been proven, this does not result in a full acquittal. The court must then refer the matter to ACAT to have the accused assessed under the Mental Health Act.

ACAT may then make one of the following orders.

Psychiatric treatment order

A psychiatric treatment order (PTO) is made under section 59 of the Mental Health Act. A 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 involuntary treatment in a mental health facility. It may also impose restrictions on the person’s communication with others.

Community care order

A community care order (CCO) is made under section 66 of the Mental Health Act. A 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 someone else;
• Is suffering, or is likely to suffer, serious mental or physical deterioration.

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

A thorough consultation process must occur before ACAT makes 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.