Drope v. Missouri (Supreme Court, 1975): The Supreme Court held that any evidence of a defendant’s possible incompetence to stand trial must be addressed regardless of the stage of proceedings. The court found a number of factors may call for a competency evaluation: (1) Evidence of a defendant’s irrational behavior; (2) The defendant’s demeanor at trial; (3) Any prior medical opinion on the defendant’s competency. While all of these factors are relevant in determining further inquiry into competency, just one factor is sufficient to warrant further investigation.