Cheyenne · Laramie County · Wyoming · (307) 333-7539
Your son, your wife, your brother was not themselves when this happened. You know it. The question is whether Wyoming law will recognize it, and what happens to them if it does.
In Wyoming, “not guilty by reason of mental illness” is a narrow legal test. The defense has to prove it, a jury decides it, and even a win is followed by a court process that can last longer than the sentence would have. Most families learn all of that in the week it matters. This page explains the plea, how the process runs, and what the verdict means afterward.
What NGMI means under Wyoming law
The rule is in Wyo. Stat. § 7-11-304(a). A person is not responsible for criminal conduct if, at the time of the conduct, as a result of mental illness or deficiency, they lacked substantial capacity either to appreciate the wrongfulness of their conduct or to conform their conduct to the requirements of law.
Two things in that sentence do most of the work. First, the question is about the moment of the offense, not about how the person is doing now. Second, there are two separate ways to meet it. A person who understood the act was wrong but could not stop themselves can qualify. A person who could control their conduct but did not understand it was wrong can also qualify. The defense only has to prove one.
The statute also draws a line around what counts. Under § 7-11-304(b), an abnormality shown only by repeated criminal or antisocial conduct is not a mental illness or deficiency. “Mental deficiency” is defined in § 7-11-301 as a defect attributable to intellectual disability, brain damage, or cognitive disability. The diagnosis matters less than the connection between the condition and the conduct on the day in question.
NGMI is not the same as competency
People run these two together, and they answer different questions.
Competency (Wyoming calls it fitness to proceed, §§ 7-11-302 and 7-11-303) asks whether the defendant can understand the proceedings and help their lawyer right now. If not, the case pauses for treatment and the question is revisited. It is about the present.
NGMI asks whether the defendant was responsible at the time of the offense. It is about the past. A person can be fully competent to stand trial and still have been unable to appreciate what they were doing months earlier. In a serious case both questions usually come up, and the order in which they are handled matters.
How the plea is raised
The plea is entered at arraignment, orally or in writing, and the court can allow it later for good cause (§ 7-11-304(c)). Once it is entered, the court must order an examination by a designated examiner: a licensed psychiatrist, or a physician or licensed psychologist with forensic training (§ 7-11-301). The examination can happen at the Wyoming State Hospital, at a local mental health center, or at the jail. A commitment for the examination is limited to 45 days, and the court may approve an extension.
The examiner’s report must state its findings, the data behind them, and the reasoning that connects the two. It goes to the prosecutor and defense counsel, not to the public. Within five days of receiving it, either side can ask for a second examination by a designated examiner of its own choosing. A defense lawyer who lets that window close has given up the most important tool the statute provides.
What the defendant says during the examination is protected. Under § 7-11-304(h), those statements can be used only on the question of mental condition, not guilt, unless the defendant testifies and the statements are used to impeach. Clients need to understand that rule, and its limits, before they sit down with the examiner.
Two burdens at trial
An NGMI trial runs on two burdens of proof at once (§ 7-11-305). The State must still prove every element of the offense beyond a reasonable doubt. That never changes. The defense then carries the burden of proving mental illness or deficiency by the greater weight of the evidence. It is a lower standard than the State’s, but it is the defense’s to carry.
Wyoming also limits who can give the jury an opinion on responsibility. Only the designated examiners who actually evaluated the defendant may testify to whether the defendant was responsible. Other experts can explain the methods and the science, but they cannot give the answer. That makes the choice of examiner, and the second-examination right, the center of the case.
The jury receives an additional verdict form: not guilty by reason of mental illness or deficiency excluding responsibility. It sits alongside guilty and not guilty. The defense has to make the jury comfortable choosing it.
What the verdict means afterward
An NGMI verdict is not an ordinary acquittal, and families should not expect their loved one to walk out of the courtroom. Under § 7-11-306, the court chooses one of three dispositions: discharge, conditional release under supervision, or commitment to the Wyoming State Hospital or another designated facility. Commitment follows when the person is mentally ill or deficient and presents a substantial risk of danger to themselves or others.
Commitment has no fixed end date. After 90 days, the facility can apply for discharge, and the person can petition the court. On the person’s own petition, they must prove by a preponderance of the evidence that they no longer meet the standard. Where the State opposes the facility’s recommendation to release, the State carries the burden.
The practical point: for a misdemeanor or a low-level felony, an NGMI verdict can mean more time in custody than a conviction would. For a serious felony, it can mean treatment instead of prison and a path to supervised release that the Department of Corrections does not offer. Whether to raise the plea at all is a strategic decision, made with the whole timeline in view.
Both chairs
Francis H. McVay has sat on both sides of the courtroom. As a Deputy County and Prosecuting Attorney in Park County, he charged misdemeanors and felonies and handled juvenile and Title 25 matters, and he saw how the State answers a mental illness plea. As Senior Assistant Appellate Counsel with the Wyoming State Public Defender, he briefed and argued Walker v. State, 2022 WY 158, in which the Wyoming Supreme Court reversed two convictions under plain-error review and ordered a new trial on them. NGMI cases are built on expert reports, examiner testimony, and jury instructions, which is exactly where appellate error lives. He is a graduate of the Gerry Spence Trial Lawyers College.
Mr. McVay briefed and argued Walker v. State as Senior Assistant Appellate Counsel for the Wyoming State Public Defender. The matter was not handled by Deep Waters Law, L.L.C. Prior results do not guarantee a similar outcome in any other matter.
Frequently asked questions
What does NGMI stand for in Wyoming?
Not guilty by reason of mental illness or deficiency. It is the verdict a jury can return under Wyo. Stat. § 7-11-305 when the defense proves, by the greater weight of the evidence, that the defendant lacked substantial capacity at the time of the offense to appreciate the wrongfulness of the conduct or to conform it to the law.
Is the insanity defense the same as NGMI?
Yes. Wyoming’s statute does not use the word “insanity.” The plea and verdict are called not guilty by reason of mental illness or deficiency, and the test in § 7-11-304(a) is what most people mean by an insanity defense.
Who has to prove mental illness?
The defense, by the greater weight of the evidence. The State still has to prove every element of the crime beyond a reasonable doubt. Only the designated examiners who evaluated the defendant may give the jury an opinion on responsibility.
How long is the mental evaluation?
A commitment for the examination is limited to 45 days under § 7-11-304(d). The examination can also be done outpatient, at a local mental health center, or at the jail. Either side has five days after the report to request a second examination.
If someone is found NGMI, do they go free?
Usually not right away. The court chooses between discharge, supervised release, and commitment to the Wyoming State Hospital. Commitment has no fixed end date. After 90 days the person can petition for discharge.
Can what I tell the examiner be used against me?
Not on the question of guilt. Under § 7-11-304(h), statements made during the examination are admissible only on mental condition, unless you testify and they are used to impeach you, or in a later perjury prosecution. Talk to your lawyer before the examination about what that protection does and does not cover.
When should we call?
Before arraignment if at all possible. The plea, the examination, the second-examiner request, and the competency question all run on clocks that start early. If a family member has been arrested and has a history of serious mental illness, call the same day.
Talk to a lawyer today
The examination clock starts at arraignment. If someone you love has been arrested and has a history of serious mental illness, call today.
Call (307) 333-7539. Answered 24/7, including weekends. Or request a free consultation.
Related
The law is not settled until it is just.
This page describes Wyoming law in general terms as of September 2026 and is not legal advice. Every matter turns on its own facts. Contacting Deep Waters Law does not create an attorney-client relationship.