disturbance existed. English diminished responsibility
permits the reduction of the charge to manslaughter if
the defendant killed in a state of substantially impaired
mental responsibility arising from mental abnormality.
Neither doctrine negates the lack of intent or conscious
awareness of a very great risk of death that is required
for the prosecution to prove murder. Both simply
reduce the degree of conviction and, thus, punishment
and stigma because mental abnormality diminishes
culpability. These partial responsibility doctrines exist
only within the law of homicide, but in principle, both
operate and could be formally treated as generic affir-
mative defenses of partial excuse, because nothing in
the language of either doctrine entails that it applies
only to homicide.
Many jurisdictions in the United States and in
English law also contain the provocation/passion
doctrine, which reduces a murder to manslaughter if
the defendant killed subjectively in the “heat of pas-
sion” in immediate response to a “legally adequate”
or “objective” provocation—that is, a provoking
event, such as finding one’s spouse in the act of adul-
tery, that would create an inflamed psychological
state in a reasonable person. The defendant kills
intentionally and is criminally responsible, but the
provocation/passion doctrine reduces the degree of
blame and punishment. The rationale supporting this
mitigating doctrine is controversial, but one interpre-
tation is that psychological states such as “heat of
passion” diminish rationality and responsibility and
the defendant is not fully at fault for being in such a
diminished condition because the provocation was
sufficient to put even a reasonable person in such a
state. In this interpretation, the provocation/passion
doctrine is a form of partial excuse related to but nar-
rower than extreme emotional disturbance and dimin-
ished responsibility.
In jurisdictions that give judges unguided or guided
sentencing discretion, mental abnormality is a factor
traditionally used to argue for a reduced sentence.
Many capital sentencing statutes explicitly mention
mental abnormality as a mitigating condition, and
some even use the language of the insanity defense or
the extreme emotional disturbance doctrine as the mit-
igation standard. The partial excuse logic of such sen-
tencing practices is conceded and is straightforward. A
criminally responsible defendant whose behavior sat-
isfied all the elements of the offense charged, includ-
ing the mens rea, and who has no affirmative defense
may nonetheless be less responsible because mentalabnormality substantially impaired the defendant’s
rationality.Stephen J. MorseSee alsoCriminal Responsibility, Defenses and Standards;
Mens Rea and Actus ReusFurther Readings
American Law Institute. (1962). Model Penal Code.
Philadelphia: Author.
Arenella, P. (1977). The diminished capacity and diminished
responsibility defenses: Two children of a doomed
marriage. Columbia Law Review, 77,827–865.
Clark v. Arizona, 548 U.S. ____ 126 S. Ct. 2709 (2006).
Fingarette, H., & Hasse, A. F. (1979). Mental disabilities and
criminal responsibility. Berkeley: University of California
Press.
Horder, J. (1992). Provocation and responsibility.Oxford,
UK: Clarendon Press.
Mackay, R. D. (1995). Mental condition defenses in the
criminal law. Oxford, UK: Clarendon Press.
Morse, S. J. (1984). Undiminished confusion in diminished
capacity. Journal of Criminal Law and Criminology, 75,
1–55.
Morse, S. J. (1993). Diminished capacity. In S. Shute,
J. Gardner, & J. Horder (Eds.),Action and value in
criminal law(pp. 239–278). Oxford, UK: Clarendon Press.DIPLOMATES IN
FORENSICPSYCHOLOGY
Diplomates in forensic psychology are dually certified
by the American Board of Forensic Psychology
(ABFP) and its parent organization, the American
Board of Professional Psychology (ABPP), as experts
in applying the science and profession of psychology
to U.S. law and the U.S. legal system.
The certification process consists of four distinct
phases: initial application, written examination, prac-
tice sample review, and oral examination. The appli-
cant must possess a doctoral degree in psychology
from a program acceptable to the ABPP. A program is
automatically deemed acceptable if accredited by the
American Psychological Association (APA) or
the Canadian Psychological Association or if listed by
the Association of State and Provincial Psychology
Boards (ASPPB). Acceptability is also presumed if220 ———Diplomates in Forensic PsychologyD-Cutler (Encyc)-45463.qxd 11/18/2007 12:42 PM Page 220