Brett C. Trowbridge, The New Diminished Capacity Defense in Washington A report from the Trowbridge Foundation, 36 Gonz. L. Rev. 497 (2001).
A criminal defendant must have a requisite mental state to commit a crime in Washington. RCW 9A.08.010(1) lists four culpable mental states: intent, knowledge, recklessness, or criminal negligence. In a diminished capacity case, the State has the burden to prove that a defendant formulated the appropriate mental state beyond a reasonable doubt. If a defendant prevails in a diminished capacity defense, he will either be acquitted or convicted of a lesser offense than the one charged. In contrast, an insanity defense is an affirmative defense for which a defendant has the burden of proving his insanity at the time of the incident by a preponderance of the evidence. If a defendant prevails in an insanity defense, he will likely be sent to a state mental hospital for treatment and may remain a patient at the hospital for up to the maximum sentence for the crime charged. An insanity defense requires a “mental disease or defect” to be the reason for the incapacitation. Since any incapacitating factor can be used in a diminished capacity defense, including voluntary intoxication, the diminished capacity defense has become more popular than the insanity defense in Washington… Read more