Competency is a preliminary fact question for the judge to make before a witness is permitted to testify. The types of people that the issue of competency arises are: (1) Children. (2) Mental incompetents. (3) Criminals. (4) Atheists. (5) Narcotics addicts. More details; (1) Children: The trial judge must be satisfied that the child possesses the ability to observe, recollect, and communicate.(2) Mental Incompetents: Mental unsoundness must be to such a degree that the person's ability to perceive, recall, and testify are so impaired that the witness' testimony is worthless. The requirements for criminals, atheists, and narcotic addicts to qualify as competent to testify are: None of them are incompetent to testify. These situations only affect the weight of their evidence, not their competency.
A district court must hold a competency hearing following a showing of reasonable cause for believing the defendant may be incompetent. United States v. Williams, 819 F.2d 605, 608 (5th Cir. 1987); United States v. Morgan, 559 F.2d 397 (5th Cir. 1977).