This is written from a Queensland perspective, but similar laws apply throughout The Commonwealth.
Some of the general principles established over time through case law and medical practice are:
- every adult of sound mind has a right to refuse medication and treatment
- any medication or health care treatment provided without consent is a trespass
- consent to medication and treatment is distinct from the duty to warn about potential risks (distinguished by the fact that a failure to warn can give rise to a separate cause of action)
- a patient has a right to refuse medication and treatment
- legislative exemptions permit medicating and treatment without consent in limited circumstances such as in an emergency
An adult is presumed to have the capacity to consent to or refuse medication and treatment unless and until that presumption is rebutted.
For consent to be valid, it must be given voluntarily. A voluntary decision is one that is made freely by a patient in response to an understanding of the medication and treatment options. The decision must be free from undue pressure, coercion or manipulation.
The absence of a valid consent is a determining factor in establishing liability for civil assault or trespass.
The Queensland Criminal Code 1899 s.245 definition of assault is:
“(1) A person who strikes, touches or moves or otherwise applies force of any kind to the person of another, either directly or indirectly, without the other person’s consent, or with the other person’s consent if a consent is obtained by flawed, or who by any bodily act or gestures attempts or threatens to apply force of any kind to the person of another without the other person’s consent, under such circumstances that the person making the attempt or threat has actually or apparently a present ability to affect the person’s purpose, is said to assault that other person and the act is called an assault.”
So as discussed above, the general principle of consent is that every adult of sound mind has a right to refuse medication and treatment.