Diminished Capacity Definition and Legal Meaning

On this page, you'll find the legal definition and meaning of Diminished Capacity, written in plain English, along with examples of how it is used.

What is Diminished Capacity?

n. A psychological term that is used in criminal trials to refer to the accused not being insane, but being under emotional distress, physical conditions or factors that affected their ability to fully comprehend the nature of their actions. In an attempt to remove the element of premeditation or criminal intent, it is raised by the defense to obtain a conviction for a lesser crime. For example: manslaughter instead of murder. Juries have been overly impressed by psychiatric testimony. A notorious instance was in People v. Dan White, the admitted killer of Sand Francisco Mayor George Moscone and Supervisor Harvey Milk. White received a manslaughter conviction on the basis that he had diminished capacity due to the sugar content of his blood which was due to eating “Twinkies.”