<P> Non-voluntary euthanasia is conducted when the consent of the patient is unavailable . Examples include child euthanasia, which is illegal worldwide but decriminalised under certain specific circumstances in the Netherlands under the Groningen Protocol . </P> <P> Involuntary euthanasia is conducted against the will of the patient . </P> <P> Voluntary, non-voluntary and involuntary types can be further divided into passive or active variants . Passive euthanasia entails the withholding treatment necessary for the continuance of life . Active euthanasia entails the use of lethal substances or forces (such as administering a lethal injection), and is the more controversial . While some authors consider these terms to be misleading and unhelpful, they are nonetheless commonly used . In some cases, such as the administration of increasingly necessary, but toxic doses of painkillers, there is a debate whether or not to regard the practice as active or passive . </P> <P> Euthanasia was practiced in Ancient Greece and Rome: for example, hemlock was employed as a means of hastening death on the island of Kea, a technique also employed in Marseilles . Euthanasia, in the sense of the deliberate hastening of a person's death, was supported by Socrates, Plato and Seneca the Elder in the ancient world, although Hippocrates appears to have spoken against the practice, writing "I will not prescribe a deadly drug to please someone, nor give advice that may cause his death" (noting there is some debate in the literature about whether or not this was intended to encompass euthanasia). </P>

What are the two commonly recognized forms of passive euthanasia
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