In fact, before recording dying declaration, the status of mental fitness of the the subject is essential component. If it is recorded by medical practitioner, then he has to declare mental fitness of subject. In case medical practitioner is not available, then magistrate or other person who record dying declaration must ask and record them in writing the normal questions and their answers given by the subject so that his/her fitness of mental status may be determined in the court..

If soundness of mental state is not proved, then statement recorded can not be treated as dying declaration. In India, Munnu Raja v. The State of Madhya Pradesh 1976 AIR 2199, case decided by the Supreme Court of India has dealt the issue in great detailed.

There are some recent relevant articles on this subject matter. There is no doubt in the fact that the mental state of the victim is an important element.  Beside acute brain dysfunction occasioned by shock, there are instances where the medication administered have triggered some side effects which also have the potential of affecting the mental state of the victim.  This other dimension is quite important but not often emphasized in relevant literature. 

Find below some relevant sources:

- Myers, J. E. (2015). Ohio v. Darius Clark: A real-life whodunit. Psychology, Public Policy, and Law, 21(4), 383.

-Cheema, S. A. (2015). Corroborating Evidence in Pakistan: A Mechanism to Fill Reliability Vacuum. Available at SSRN 2667365.

-Lyons, D. P. (2015). Fundamentals of Jail & Prison Administrative/Internal Investigations. AuthorHouse.

- Textbook of Forensic Medicine and Toxicology

Hi,

Basically the admissibility criteria for dying declarations will be stated in your EVIDENCE ACT. It is an exception to the hearsay Rule.

You could look at some good articles:

'The Admissibilty of Dying Declarations' Fordham Law Review Volume 38 | Issue 3 Article 5

Robert H. Klugman , 'Some Factors Affecting the Admissibility of Dying Declarations'

Journal of Criminal Law and Criminology Volume 39 | Issue 5 Article 7.

Best Wishes

 Well Rodell,

Dying declaration has been considered as an important evidence throughout the world. Though the question you raised is of much importance as the fitness of deceased is of great concern. Indian Supreme Court has been liberally considered the DDs if the Court satisfies regarding the truthfulness, even no certificate of any Doctor of Magistrate is attached and even oral Dying declaration given to any person is also admissible. Recently Indian Supreme Court in Vijay Pal Versus State (GNCT) of Delhi 2015 (4) SCC 749 Can be oral or in writing or in any adequate method of communication. It is duty of the Court to examine whether it is voluntary, truthful & made in conscious state of mind & without influence, unless there existed some inherent and apparent defect, can be relied upon.

Ultimately everything depends upon the satisfaction of the Court regarding truthfulness of the witness of oral or written Dying Declaration

For the US, the Dying declaration is in Rule 804 of the US Federal Rules of Evidence, "Hearsay Exceptions; Declarant Unavailable".

A good reference/legal explaination is in the Fordham Law Review Vol.38, Issue 3 Article 5: The Admissibility of Dying Declaration.

Link: http://ir.lawnet.fordham.edu/cgi/viewcontent.cgi?article=2018&context=flr

hello, You are right sir that a victim in shock can suffer acute brain dysfunction that affects the veracity of his "dying declarations" but mental fitness is an essential component. A person must be in fit state of mind before giving any statement. You can challenge at any time in the court or prove with a doctor's certificate about his mental fitness.

The dying declaration exception to the rule against hearsay permits out of court statements by a person to prove the matter they asserted out of court. At its narrowest the witness must be dead, that is generally no longer the case. They must however been in imminent fear of death. Their testimony is allowed because it is presumed the fear of death will make them more honest, whether for religious or practical grounds, and also because the dead witness is as unavailable as it gets. scholar.google.com or ssrn.com are good starting points. i do not yet know how to research through academia.edu or researchgate. this is a well known topic. u.s. federal rules of evidence fre are online for free as a pdf just sarch.