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In order for a person to be held criminally responsible for their actions and attract criminal punishment, it is necessary for the prosecution to prove that his or her actions were conscious, voluntary and willed. A person who is asleep, unconscious, or operating in a dissociative state cannot be said to be criminally culpable.


When an act is committed in the state of automatism, this means that the person committing the offence did so without any control or direction over what was being done. That is, their actions were involuntary and independent of their will.


Automatism refers to circumstances where a person is disassociated from the act, such that they are simply unable to control their own actions or conduct. When attempting to rely on the defence of automatism, it must be demonstrated that the accused’s actions were the product of some external factor which was out of their control. You are not able to use this defence if your actions were self-induced, or within your control, for example you overdosed on drugs or alcohol to put you in a dissociative state. It is recognised by cases such as R v Falconer (1990) 171 CLR 30 and R v Youssef (1990) 50 A Crim R 1, that criminal responsibility does not attach to an act done in a state of automatism, that is, where the act is not done in consciousness of the nature of the act and in exercise of a choice to do an act of that nature


There are two types of automatism, namely sane and insane automatism.


Sane automatism refers to circumstances where a non-recurrent mental malfunction results in a person being unable to control their actions. The mental malfunction must be caused by an external factor, which was out of the person’s control. This may involve a physical incapacitation, or a psychological one.


Examples of sane automatism include offences committed whilst sleepwalking, suffering an epileptic fit (depending on its aetiology) or while under the influence of anaesthetic. Sane automatism can also occur when one’s conduct is the result of severe emotional shock or post traumatic distress disorder. In most circumstances, expert evidence and medical records are required to raise this defence.


The following elements or features must be present when raising the defence of sane automatism:

  1. There is an external factor that caused the person to act the way they did;

  2. The actions were involuntary or unintentional; and

  3. The actions were not a result of a mental illness, rather a non-recurrent mental malfunction.


When sane automatism is raised as a defence, it is not the accused’s responsibility to prove that they were acting in a state of automatism. Rather, the prosecution must negate the defence and prove that the accused was acting voluntarily.


If the prosecution are unable to negate the defence of sane automatism, the Court may accept that your actions were involuntary or otherwise consider that the prosecution have not proven their case beyond reasonable doubt. Therefore, the Court would find you not guilty.


Insane automatism can be raised when the accused has a ‘disease of the mind’ present. This means that the accused’s state of mind was one of disease, disorder or disturbance arising from some condition that recurs. This disease or illness must have influenced the person’s actions or understanding of those actions, that is, there ought to be a connection.


When the defence of insane automatism is raised, the accused must prove on the balance of probabilities that:


  1. They were suffering from a ‘disease of the mind’ (i.e. mentally ill) at the time of the act; and

  2. As a result of this illness or disease, the accused did not appreciate the nature and quality of that act, or, did not know that it was wrong.

If an accused is found to have acted in a state of insane automatism, meaning that the accused was mentally ill, they will be found ‘not guilty by way of mental illness’. A finding of ‘not guilty’ and ‘not guilty by way of mental illness’ are very different results and could result in detention in a mental health facility for an indefinite period of time.

If you think you may have the defence of automatism, it is important that you seek legal advice. If you wish to discuss your options, please contact KF Lawyers to arrange for a free initial consultation.

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