A person who is directly affected must give consent. Only in exceptional circumstances can it be given by another person e.g. on behalf of mentally ill patients. In the event that a person is unable to consent, consent can be given by a person who has a legal right to consent on behalf of another person, e.g. guardian or curator.

Adults who have a legal capacity (the ability to make legal decision) who are of “sound and sober mind” can give valid consent to medical treatment (consent recognised by law). Adults without legal capacity (e.g. people who are mentally ill or have a mental disability) cannot give consent without assistance. Couples must consent to treatment individually – one partner in a relationship cannot consent to treatment on behalf of the other partner.

Children over 12 years can also give their own consent to medical treatment. When a child is too young to consent, either one of their parents or guardians must give consent. (See: Children and Youth and HIV/AIDS)