Classification of euthanasia
Euthanasia may be classified according to whether a person gives informed consent into three types: voluntary, non-voluntary and involuntary.[24][25]
There is a debate within the medical and bioethics literature about whether or not the non-voluntary (and by extension, involuntary) killing of patients can be regarded as euthanasia, irrespective of intent or the patient's circumstances. In the definitions offered by Beauchamp and Davidson and, later, by Wreen, consent on the part of the patient was not considered as one of their criteria, although it may have been required to justify euthanasia.[12][26] However, others see consent as essential.