Euthanasia is a desperate act that comes in many forms according to the definitions below. Consider the motifs when considering causes. Each case has its own circumstances and many ethical, moral, and legal considerations are taken into account. The purpose is to relieve suffering of an individual or animal and a difficult judgement is at stake. There are many controversial issues in regard to religion also.
Voluntary euthanasia: When the person who is killed has requested to be killed.
Non-voluntary: When the person who is killed made no request and gave no consent.
Involuntary euthanasia: When the person who is killed made an expressed wish to the contrary.
Assisted suicide: Someone provides an individual with the information, guidance, and means to take his or her own life with the intention that they will be used for this purpose. When it is a doctor who helps another person to kill themselves it is called "physician assisted suicide."
Euthanasia By Action: Intentionally causing a person's death by performing an action such as by giving a lethal injection.
Euthanasia By Omission: Intentionally causing death by not providing necessary and ordinary (usual and customary) care or food and water.
The factors that are often taken into consideration in deciding whether or not to seek or offer euthanasia are:
an end to suffering
a person's desire not to be a burden on others
the caregivers' desire to get their life back (seldom admitted, but a real factor nonetheless)
(even less often admitted), a person's desire to get insurance $ for loved ones or another's desire to speed up an inheritance
Note that the key difference between euthanasia and suicide is that in the case of euthanasia the individual is generally suffering from a fatal condition.
Euthanasia is assisted suicide. In animals, it is often referred to as "putting to sleep." For people, it is a crime.
I'm not sure what causes of euthanasia would be, exactly, since it isn't a disease but rather an action. Someone would commit euthanasia, or help someone commit suicide, if that person were sick or dying. A famous example of this was Dr. Kevorkian. For animals, euthanasia happens when animals are sick or if an animal shelter has too many animals to care for.
The effect of euthanasia is death.
Euthanasia is a very controversial topic. Some people are for it while others are against it. The people who are for euthanasia feel that people should have the right to die with dignity. They feel that if someone is painfully dying of some incurable disease, then they should have the right to not have to go through that. On the other hand, people who are against euthanasia feel that if it were to be legalized, where does it stop. Also, who has the right to decide when life is over.
The causes of euthenasia are usually advanced illness and a person's desire to end the suffering. The effects vary. Those who assist suicides can face criminal charges. They also have to live with ending a life, especially the life of a loved one.