The DOJ proposal is a proposed change in ATF regulations that amends the definitions of a person “Adjudicated as a Mental Defective” and “Committed to a Mental Institution.”

The revised definition clarifies that the statutory terms “adjudicated as a mental defective” and “committed to a mental institution” include persons who are found incompetent to stand trial or not guilty by reason of mental disease or defect; persons lacking mental responsibility or deemed insane; and persons found guilty but mentally ill, regardless of whether these determinations are made by a state, local, federal or military court. The proposed regulation also clarifies that the statutory term includes a person committed to involuntary inpatient or outpatient treatment (my emphasis.)

You can read the proposal at the Federal Register here.

The HHS proposed rule change is a modification to HIPAA. You can read it here. It would:

modify the Health Insurance Portability and Accountability Act of 1996 (HIPAA) Privacy Rule to expressly permit certain HIPAA covered entities to disclose to the National Instant Criminal Background Check System (NICS) the identities of individuals who are subject to a Federal “mental health prohibitor” that disqualifies them from shipping, transporting, possessing, or receiving a firearm.

...Among the persons subject to the Federal mental health prohibitor are individuals who have been involuntarily committed to a mental institution; found incompetent to stand trial or not guilty by reason of insanity; or otherwise have been determined by a court, board, commission, or other lawful authority to be a danger to themselves or others or to lack the mental capacity to contract or manage their own affairs, as a result of marked subnormal intelligence or mental illness, incompetency, condition, or disease.

Under this proposal, only covered entities with lawful authority to make adjudication or commitment decisions that make individuals subject to the Federal mental health prohibitor, or that serve as repositories of information for NICS reporting purposes, would be permitted to disclose the information needed for these purposes. This disclosure would be restricted to limited demographic and certain other information and would not include medical records, or any mental health information beyond the indication that the individual is subject to the Federal mental health prohibitor.

The DOJ change seems to me to be more like an amendment of the Gun Control Act than a clarification. The notice in the federal register is titled "Amended Definition of “Adjudicated as a Mental Defective” and “Committed to a Mental Institution.” The Notice also includes this statement:

The Department recognizes that the term “mental defective” is outdated, but it is included in the statute and cannot be amended by regulation.

In other words, while the Attorney General can authorize ATF, a DOJ agency, to enforce the Gun Conrol Act of 1968, he can't authorize ATF to change what it says.

18 USC 922(g) is the section of the Gun Control Act that lists the classes of persons who are prohibited from possessing, selling, shipping or transporting guns. It includes a person who:

"(4) Has been adjudicated as a mental defective or committed to a mental institution;

I don't think a person involuntarily committed to outpatient treatment is a person "committed to a mental institution."

(In addition to the mentally defective and committed, the statute's prohibitions include (among others) a person who is "an unlawful user of or addicted to any controlled substance"; undocumented aliens and those admitted under a nonimmigrant visa; anyone with dishonorable discharges from the military' and anyone with a misdemeanor domestic violence conviction.)

DOJ is inviting public comments on two additional issues:

• whether the statutory term “adjudicated as a mental defective” includes an adjudication that occurred when the person was under the age of 18.
• whether the statutory term “committed to a mental institution” includes an involuntary commitment that occurred when the person was under the age of 18.