Mental Illness Alone Does Not Render A Witness Incompetent; Inability To Understand Questions Or Answer Rationally Is The True Test
A person of unsound mind is not automatically incompetent to testify. Under Section 118 of the Indian Evidence Act and Section 124 of the Bharatiya Sakshya Adhiniyam, competency of a witness depends on ability to understand questions and give rational answers — not on the mere existence of mental illness. Incompetency arises only where the mental condition actually prevents such understanding or rational response. Failure of the investigating officer to identify a witness as mentally challenged at the stage of recording her statement does not vitiate the prosecution's case where the witness demonstrates competency during trial through a voir dire examination.
