Us Code § 850a - Art. 50a. Defense of lack of mental responsibility

Full text of Us Code United States Code § 850a — Art. 50a. Defense of lack of mental responsibility, with citation guidance and answers to common questions.

§ 850a. Art. 50a. Defense of lack of mental responsibility

(a) It is an affirmative defense in a trial by court-martial that, at the time of the commission of the acts constituting the offense, the accused, as a result of a severe mental disease or defect, was unable to appreciate the nature and quality or the wrongfulness of the acts. Mental disease or defect does not otherwise constitute a defense.

(b) The accused has the burden of proving the defense of lack of mental responsibility by clear and convincing evidence.

(c) Whenever lack of mental responsibility of the accused with respect to an offense is properly at issue, the military judge shall instruct the members of the court as to the defense of lack of mental responsibility under this section and charge them to find the accused—

(1) guilty;

(2) not guilty; or

(3) not guilty only by reason of lack of mental responsibility.


(d) Subsection (c) does not apply to a court-martial composed of a military judge only. In the case of a court-martial composed of a military judge only, whenever lack of mental responsibility of the accused with respect to an offense is properly at issue, the military judge shall find the accused—

(1) guilty;

(2) not guilty; or

(3) not guilty only by reason of lack of mental responsibility.


(e) Notwithstanding the provisions of section 852 of this title (article 52), the accused shall be found not guilty only by reason of lack of mental responsibility if—

(1) a majority of the members of the court-martial present at the time the vote is taken determines that the defense of lack of mental responsibility has been established; or

(2) in the case of a court-martial composed of a military judge only, the military judge determines that the defense of lack of mental responsibility has been established.

(Added Pub. L. 99–661, div. A, title VIII, §802(a)(1), Nov. 14, 1986, 100 Stat. 3905; Pub. L. 114–328, div. E, title LVII, §5233, Dec. 23, 2016, 130 Stat. 2915.)


Editorial Notes

Amendments

2016—Subsec. (c). Pub. L. 114–328, in introductory provisions, struck out ", or the president of a court-martial without a military judge," after "the military judge".


Statutory Notes and Related Subsidiaries

Effective Date of 2016 Amendment

Amendment by Pub. L. 114–328 effective on Jan. 1, 2019, as designated by the President, with implementing regulations and provisions relating to applicability to various situations, see section 5542 of Pub. L. 114–328 and Ex. Ord. No. 13825, set out as notes under section 801 of this title.

Effective Date

Pub. L. 99–661, div. A, title VIII, §802(b), Nov. 14, 1986, 100 Stat. 3906, provided that: "Section 850a of title 10, United States Code, as added by subsection (a)(1), shall apply only to offenses committed on or after the date of the enactment of this Act [Nov. 14, 1986]."

About This Section

10 U.S.C. § 850a is part of Title 10 of the United States Code. The United States Code is the official codification of federal statutes maintained by the Office of the Law Revision Counsel of the U.S. House of Representatives. Congress amends the Code through new public laws, which are eventually incorporated into the relevant title.

This section may be cited in legal writing as 10 U.S.C. § 850a. For the most current official text, including any recent amendments, use the official source links below. Do not rely on this page as the sole authority for legal citation or litigation.

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Sources

Source: official Us Code text · Last verified 2026-08-27

Frequently Asked Questions About Us Code § 850a

What does United States Code § 850a cover?

Section 850a ("Art. 50a. Defense of lack of mental responsibility") is part of the United States Code, the codified statutory law of Us Code. It sets out the legal rule or procedure described in the text above. Statutes are amended regularly, so always verify against the official source.

How do I cite Us Code § 850a?

A common citation format is "United States Code § 850a" (Us Code). Legal writing may require the code abbreviation, section number, and year or edition. Match the style required by your court, professor, or publisher.

Is this the official text of Us Code law?

No. This page is for research and education and may not include the most recent amendments. For official current law, check the Us Code official source linked on this page or consult a licensed Us Code attorney.

How does Us Code § 850a apply to my situation?

Statutes are interpreted in context, and application depends on your specific facts. Only a licensed attorney in Us Code can advise on how this section applies to you. Contact your state or local bar association for a referral.

Sources & Verification

Not legal advice. Verify against the official source and consult a licensed attorney in Us Code.