“Every human being has the inherent right to life. This right shall be protected by law. No one shall be arbitrarily deprived of his life.”
Article 6(1) of the ICCPR
No one shall be subjected to torture or to cruel, inhuman or degrading treatment or punishment.’
Article 7, International Covenant on Civil and Political Rights (ICCPR)
Mentally ill people and people with severe intellectual disabilities should not be executed
Customary international law prohibits the execution of prisoners who are “insane”. A number of international human rights bodies have also recognised that intellectually disabled individuals should not be subjected to the death penalty. The UN Commission on Human Rights has adopted several resolutions urging all states not to execute any person “suffering from any form of mental disorder.” These principles apply whether or not the person was mentally ill or intellectually disabled at the time of the alleged offence.
Despite widespread acceptance that the execution of the mentally ill and the intellectually disabled is unacceptable, mentally ill and intellectually disabled defendants continue to be sentenced to death and many countries have inadequate laws protecting the mentally ill and intellectually disabled from the death penalty.
“…defendants in the aggregate face a special risk of wrongful execution because of the possibility that they will unwittingly confess to crimes they did not commit, their lesser ability to give their counsel meaningful assistance, and the facts that they are typically poor witnesses and that their demeanor may create an unwarranted impression of lack of remorse for their crimes”.
The US Supreme Court in its ruling in the case of Atkins v Virginia
There is little data to indicate how many individuals with severe mental disorders are executed around the world. One major barrier to documenting the incidence of mental illness or intellectual disability among condemned prisoners is the lack of qualified mental health professionals in executing countries. In many cases prisoners do not have access to or are denied proper mental health assessments, so their mental illness or intellectual disability goes undocumented.
Another problem is that there are no international standards that govern the definition of intellectual disability. The American Association on Intellectual and Developmental Disabilities defines intellectual disability as a disability characterized by significant limitations both in intellectual functioning and in adaptive behaviour, as expressed in conceptual, social, and practical adaptive skills, that originated before the age of 18.
Intellectual disability is a disability that is markedly different from mental illness; an individual with intellectual disability may be entirely free from mental illness. A vast majority of nations conflate intellectual disability with mental illness, or leave out intellectual disability as an exclusionary category entirely and intellectually disabled individuals continue to face the death penalty around the world.
There are examples all over the world of cases of mentally ill and intellectually disabled people facing the death penalty, including many that Reprieve has worked on in the US, China, Pakistan, and Malawi.
People can develop mental health problems in prison waiting to be executed
Being held on death row under threat of death is uniquely terrifying and oppressive. For anyone, the prospect of death is terrifying. Living for years with the uncertainty of life or death, with the helplessness of having to wait for legal decisions over which the prisoner has no control, is an almost overwhelming ordeal. Many prisoners are also held in life-threatening prison conditions. International law recognises that poor prison conditions and the mental anguish associated with the fear of execution can cause a prisoner’s mental health to deteriorate.
Developing international jurisprudence supports the idea that prolonged incarceration on death row, known as “death row phenomenon”, constitutes cruel, inhuman, or degrading punishment, which is prohibited by international law.
More on Death Row Phenomenon
The psychological impact of long periods on death row awaiting execution is know as death row phenomenon.
Mental health should be considered when deciding whether or not to sentence a person to death
International law provides that the death penalty can only be imposed in very restricted circumstances. Courts around the world have held that a death sentence can only be imposed where there has been an individualised “consideration of the character and record of the individual offender and the circumstances of the particular offense”.
International tribunals and domestic courts have held that, when deciding whether or not to sentence a prisoner to death, the possibility of the prisoner’s reform and social re-adaptation must be considered and so social inquiry and psychiatric reports are necessary for all such sentence hearings.
For prisoners suffering from mental illness or intellectual disability to be identified and properly protected from execution it is necessary for there to be a mental health assessment by a properly qualified mental health professional with information from the prisoner and the prisoner’s community.
 See William A. Schabas, International Norms on Execution of the Insane and the Mentally Retarded, Criminal Law Forum, Vol. 4, 95-117, 1993, at 114 and the sources cited at 110-116; William A. Schabas, The Abolition of the Death Penalty in International Law, 3rd ed, 2002, at 375; Richard J. Wilson, The Death Penalty and Mental Illness in International Human Rights Law: Toward Abolition, Washington and Lee Law Review, Vol. 73, 1469-1499, 2016, at 1485-1486; U.N. ECOSOC, Safeguards Guaranteeing Protection of the Rights of Those Facing the Death Penalty, para. 3, E.S.C. Res. 1984/50, U.N. Doc. E/1984/92, 1984 (the death penalty shall not be carried out on persons who have become insane).
 [See, e.g., U.N. Office of the High Commissioner for Human Rights, The Question of the Death Penalty, E/CN.4/RES/2003/67, Apr. 25, 2003.]
 Roger Hood & Carolyn Hoyle, The Death Penalty: A Worldwide Perspective p.203, Oxford University Press, 4th ed., 2008
 Atkins v Virginia 536 U. S. 304 (2002) at 305.
 U.N. ECOSOC, Capital punishment and implementation of the safeguards guaranteeing protection of the rights of those facing the death penalty: Report of the Secretary-General, para. 88, U.N. Doc. E/2005/3, Mar. 9, 2005
 The American Association on Intellectual and Developmental Disabilities, Frequently Asked Questions on Intellectual Disability and the AAIDD Definition, http://aaidd.org/intellectual-disability/definition/faqs-on-intellectual-disability#.V761HGVWh-s
 For more information see http://www.deathpenaltyworldwide.org/intellectual-disability.cfm
 Francis v. Jamaica, Communication No. 606/1994, U.N. Doc. CCPR/C/54/D/606/1994, Aug. 3, 1995
 See, e.g., Pratt and Morgan v. The Attorney General of Jamaica, 3 SLR 995, 2 AC 1, 4 All ER 769 (Privy Council 1993) (en banc); Soering v. United Kingdom, 11 Eur. Hum. Rts. Rep. 439 (1989) (European Court of Human Rights)
 Article 7 of the ICCPR provides that “[n]o one shall be subjected to torture or to cruel, inhuman, or degrading treatment or punishment.” Other human rights treaties contain identical language. See, e.g., European Convention on Human Rights, art. 3; American Convention on Human rights, art. 5; African Charter on Human and Peoples Rights, art. 5; Convention Against Torture and Other Cruel, Inhuman, or Degrading Treatment or Punishment, art. 16.
 Article 6 of the International Covenant on Civil and Political Rights
 Woodson v. North Carolina, 428 U.S. 280 (1976) at 304. In 1983, India’s Supreme Court likewise held that the mandatory death sentence was unconstitutional. Mithu v. State of Punjab, 1983 SCR (2) 690, Supreme Court of India, 1983
 Pipersburgh v. The Queen (JCPC, 2008), Harry Wilson v. The Queen (Court of Appeal, Saint Vincent and the Grenadines, 2005)