Christian views on suicide
There has been much debate over the Christian view on suicide, with early Christians believing that suicide is sinful and an act of blasphemy. In modern times, some Christian churches reject this idea, although others still espouse and teach this view.
In the fifth century, St. Augustine wrote the book The City of God, in it making Christianity's first overall condemnation of suicide. His biblical justification for this was the interpretation of the commandment, "Thou shalt not kill", as he sees the omission of "thy neighbor", which is included in "Thou shalt not bear false witness against thy neighbor", to mean that the killing of oneself is not allowed either. The rest of his reasons were from Plato's Phaedo.
In the sixth century AD, suicide became a secular crime and began to be viewed as sinful. In 1533, those who committed suicide while accused of a crime were denied a Christian burial. In 1562, all suicides were punished in this way. In 1693, even attempted suicide became an ecclesiastical crime, which could be punished by excommunication, with civil consequences following. In the 13th century, Thomas Aquinas denounced suicide as an act against God and as a sin for which one could not repent. Civil and criminal laws were enacted to discourage suicide, and as well as degrading the body rather than permitting a normal burial, property and possessions of the suicides and their families were confiscated.
According to the theology of the Catholic Church, death by suicide is considered a grave matter, one of the elements required for mortal sin. The reason is that one's life is the property of God and a gift to the world, and to destroy that life is to wrongly assert dominion over what is God's and was held as despair over salvation.
In points 2281 and 2325 of the Catechism it is stated:
2281 Suicide contradicts the natural inclination of the human being to preserve and perpetuate his life. It is gravely contrary to the just love of self. It likewise offends love of neighbor because it unjustly breaks the ties of solidarity with family, nation, and other human societies to which we continue to have obligations. Suicide is contrary to love for the living God.
2325 Suicide is seriously contrary to justice, hope, and charity. It is forbidden by the fifth commandment.
The official Catechism of the Catholic Church indicated that the person who committed suicide may not always be fully right in their mind; and thus not one-hundred-percent morally culpable: "Grave psychological disturbances, anguish, or grave fear of hardship, suffering, or torture can diminish the responsibility of the one committing suicide." The Catholic Church prays for those who have committed suicide, knowing that Christ shall judge the deceased fairly and justly. The Church also prays for the close relations of the deceased, that the loving and healing touch of God will comfort those torn apart by the impact of the suicide.
Formerly, those who committed suicide were denied a Christian funeral. Pope Pius X said: "In the Fifth Commandment God forbids suicide, because man is not the master of his own life no more than of the life of another. Hence the Church punishes suicide by deprivation of Christian burial." 
- http://plato.stanford.edu/entries/suicide/#ChrPro Michael Cholbi in Stanford Encyclopedia of Philosophy article on Suicide, section 2.2 The Christian Prohibition
- "Pips Project – THE STIGMA OF SUICIDE A History". Archived from the original on March 17, 2007.
- "Ophelia's Burial".
- Dowie, J. A. (1902). Leaves of Healing. v. 11. Zion Publishing House. p. 702.
- Clemons, J. T. (1990). Perspectives on Suicide. Westminster John Knox Press. p. 55. ISBN 978-0-664-25085-0.
- Pope Pius X. Catechism of Saint Pius X. Taken from https://www.ewtn.com/library/CATECHSM/PIUSXCAT.HTM