Editing Insanity defense (section)

===Mitigating factors and diminished capacity===
The [[United States Supreme Court]] (in ''[[Penry v. Lynaugh]]'') and the [[United States Court of Appeals for the Fifth Circuit]] (in ''[[Bigby v. Dretke]]'') have been clear in their decisions that [[jury instructions]] in death penalty cases that do not ask about [[mitigating factor]]s regarding the defendant's [[mental health]] violate the defendant's [[Eighth Amendment to the United States Constitution|Eighth Amendment]] rights, saying that the jury is to be instructed to consider mitigating factors when answering unrelated questions. This ruling suggests specific explanations to the jury are necessary to weigh mitigating factors.

Diminished responsibility or diminished capacity can be employed as a mitigating factor or partial defense to crimes. In the United States, diminished capacity is applicable to more circumstances than the insanity defense. The Homicide Act 1957 is the statutory basis for the defense of diminished responsibility in England and Wales, whereas in Scotland it is a product of case law. The number of findings of diminished responsibility has been matched by a fall in unfitness to plead and insanity findings.<ref name=walker /> A plea of diminished capacity is different from a plea of insanity in that "reason of insanity" is a full defense while "diminished capacity" is merely a plea to a lesser crime.<ref name="Cornell">{{cite web|title=Diminished capacity, as opposed to not guilty by reason of insanity|url=https://www.law.cornell.edu/background/insane/capacity.html|work=Legal Information Institute: Federal Law|publisher=Cornell University Law School|access-date=19 December 2011|author=Legal Information Institute|url-status=live|archive-url=https://web.archive.org/web/20111008212843/http://www.law.cornell.edu/background/insane/capacity.html|archive-date=8 October 2011}}</ref>