Psychiatric testimony and the "reasonable person" standard.

The aim of this article is to explore the boundaries of psychiatric testimony in criminal cases. In a series of vignettes, the author describes applications of psychiatric testimony in nontraditional areas. These are criminal cases in which the defendant-who was not mentally ill-acted in response to a situation that would tend to trigger violence in many persons: protection of self or others. In scenarios involving self-defense, duress, and passion/provocation, the dynamics involve interpersonal situations that give rise to behavior that may be entirely foreign to the defendant but that could not have been avoided. The law looks at these matters through a "reasonable person" standard: what the ordinary citizen would have done. In principle, there is often no need for expert testimony, because judges and jurors are presumed able to assess reasonableness, justification, or provocation. The trier of fact, however, could use a psychiatric explanation to assess culpability. The author discusses the cases in terms of application and admissibility.