---
type: "LegalText"
title: "18 U.S.C. § 17"
description: "Insanity defense"
jurisdiction: "us"
corpus: "united_states_code"
kind: "code_section"
title_number: 18
title_name: "CRIMES AND CRIMINAL PROCEDURE"
chapter_number: "1"
chapter_name: "GENERAL PROVISIONS"
section: "17"
citation: "18 U.S.C. § 17"
status: "current"
release_point: "119-100"
release_date: "2026-06-26"
source: "official"
source_url: "https://uscode.house.gov/download/releasepoints/us/pl/119/100/xml_usc18@119-100.zip"
source_identifier: "/us/usc/t18/s17"
source_file: "data/legal/raw/us/code/title-18/usc18.xml"
source_hash: "5846259e27e273da10c7643ed0a2666adf0bec6d0c940b55316e5cce617b12b7"
raw_snapshot_hash: "1a1bbbbdb59e376ada4eb7ad1056fd68d396679ee7ab59f0561af15006122708"
text_hash: "2198db46ab7c2dc413fdd1e08bd1488341fd42aa20ac7153b59158bf6d801641"
retrieved_at: "2026-07-04"
confidence: "official"
tags: ["legal", "us-code"]
---

# 18 U.S.C. § 17 - Insanity defense

## Text

(a) Affirmative Defense.— It is an affirmative defense to a prosecution under any Federal statute that, at the time of the commission of the acts constituting the offense, the defendant, as a result of a severe mental disease or defect, was unable to appreciate the nature and quality or the wrongfulness of his acts. Mental disease or defect does not otherwise constitute a defense.

(b) Burden of Proof.— The defendant has the burden of proving the defense of insanity by clear and convincing evidence.

(Added Pub. L. 98–473, title II, § 402(a), Oct. 12, 1984, 98 Stat. 2057, § 20; renumbered § 17, Pub. L. 99–646, § 34(a), Nov. 10, 1986, 100 Stat. 3599.)