Estimated reading time: 5 minutes
Table of Contents
- What Nevada Law Actually Requires
- How the Plea Gets Filed
- Why the Defense Rarely Succeeds
- Insanity vs. Guilty But Mentally Ill
- Insanity vs. Competency to Stand Trial
- What Happens After a Not Guilty by Reason of Insanity Verdict
- Frequently Asked Questions
- About the Author
Movies have led many to believe that claiming insanity is a viable defense. In reality, it’s one of the most difficult defenses to win, especially in Nevada where the standard is narrow.
Having handled criminal cases for over 30 years, we occasionally speak with clients and potential clients who question whether claiming insanity can work for them. Like anything in this profession, it depends. But unlike other questions we get, answering this one often requires us to spend some time explaining what an insanity plea really means and what Nevada law requires in such a situation.
What Nevada Law Requires
Nevada follows a version of the M'Naghten rule, codified under NRS 174.035(6). This means that if you are pleading not guilty by reason of insanity, you’ll have the burden of proving that:
- Because of a “disease or defect of the mind,” you were in a delusional state at the time of the alleged crime; and
- Because of that delusional state, you didn’t know or understand the nature and capacity of your act, or appreciate the wrongfulness of the act.
Both of these elements must be proven, and they show how Nevada law goes beyond the common misconception that insanity pleas mean “not knowing right from wrong.”
A defendant who knew exactly what they were doing but couldn’t control the impulse to do it doesn’t meet the standard. There must be a specific delusion that shaped what the person believed was happening when the offense occurred.
There also needs to be an actual disease or defect of the mind, excluding any caused by voluntary intoxication. Drugs and alcohol, on their own, don’t support this defense.
How the Plea Gets Filed
Per Nevada law, a defendant who is pleading not guilty by reason of insanity must enter their plea at least 21 days before trial. If the deadline is missed, the defense may still be raised during trial, but only if the defendant shows good cause for the delay.
After submitting the plea, the burden of proving it rests entirely with the defense. Unlike most criminal cases, where the prosecution has to disprove a claim beyond a reasonable doubt, the insanity defense requires a defendant to affirmatively prove their case by a preponderance of the evidence – a standard that generally means “more likely than not.”
Why the Defense Rarely Succeeds
An eight-state study published in the Bulletin of the American Academy of Psychiatry and the Law found that the insanity defense is not very common nor successful. The study noted that:
- The insanity defense is used in only about 1% of all felony cases.
- Only 26% of defendants who use the defense are acquitted.
- Of those who successfully use the defense, nearly 90% had a diagnosed severe mental disorder.
- Only 7% of insanity acquittals are decided by jury. Most are decided by a judge.
The reason behind the low success rate, apart from the defense often being used in only the most serious felony cases, like murder, is that a mental illness diagnosis by itself isn't enough, especially given that Nevada’s standard is tied to a specific delusional belief rather than a general diagnosis.
Schizophrenia, bipolar disorder, or a documented psychiatric history can support the defense, but only if there's evidence connecting the diagnosis to a delusion that existed at the exact moment of the offense. Juries also tend to be skeptical, and prosecutors routinely bring in their own mental health experts to challenge the defense's evaluation.
Insanity vs. Guilty But Mentally Ill
Nevada also allows a separate verdict called guilty but mentally ill, addressed under NRS 175.533. This comes into play when a defendant is found guilty beyond a reasonable doubt, was mentally ill at the time of the offense, but didn't prove legal insanity.
A guilty but mentally ill verdict still results in a criminal conviction, with the same sentencing exposure as an ordinary guilty verdict. Under NRS 176.057, the court considers the defendant's mental illness when imposing sentence and treatment, but it doesn't reduce the underlying penalty the way an insanity acquittal does.
Insanity vs. Competency to Stand Trial
Pleading insanity and being competent (or not) to stand trial often get confused, but they address different questions at different points in a case.
- Competency to stand trial asks whether a defendant can currently understand the proceedings against them and assist in their own defense. It's evaluated before or during trial and has nothing to do with the person's mental state when the alleged crime occurred.
- An insanity defense asks about the defendant's mental state at the time of the offense itself. A person can be perfectly competent to stand trial today and still raise insanity as a defense to something that happened months or years earlier.
What Happens After a Not Guilty by Reason of Insanity Verdict
A person found not guilty by reason of insanity doesn’t automatically get to walk free.
Under NRS 175.539, the court will order the person to be taken into protected custody and transported to a forensic facility for detention pending an examination by two mental health professionals. At the hearing, both the defendant and the State can present evidence, including reports from the mental health professionals, and the court decides whether continued commitment is appropriate.
For serious charges, this process can lead to years of confinement in a psychiatric facility rather than a prison, with periodic evaluations determining when, or if, release becomes appropriate.
Frequently Asked Questions
Does an Insanity Plea Mean Someone Goes Free?
No. A successful insanity defense typically leads to commitment in a psychiatric facility, evaluated under NRS 175.539, rather than release.
Can Voluntary Intoxication Support an Insanity Defense?
No. Nevada law specifically excludes a disease or defect of the mind caused solely by voluntary intoxication from qualifying for this defense.
Is Insanity the Same as Diminished Capacity?
No. Insanity is a complete defense that, if proven, results in acquittal. A separate intent-based defense may challenge whether the State can prove the mental state required for a specific charge, but that is different from an insanity plea.
How Long Can Someone Be Committed After an NGRI Verdict?
There's no fixed term. Commitment continues based on periodic evaluations of the person's mental state, and can extend well beyond what a criminal sentence for the same offense might have been.
Can the Insanity Defense Be Raised After Trial Has Already Started?
Yes, but only with good cause shown to the court, since Nevada requires the plea to be entered at least 21 days before trial in most circumstances.
About the Author
Ross Goodman is Founder of Goodman Law Group. He is one of only two attorneys in Nevada dual-certified by the State Bar of Nevada as a Certified Specialist in Criminal Trial Advocacy and by the National Board of Trial Advocacy as a Board-Certified Criminal Trial Law Specialist. A lifelong Las Vegas resident and retired U.S. Marine Corps Major, Ross has spent nearly three decades handling complex criminal defense strategies, including cases involving mental health and competency issues, throughout Nevada.
If you're weighing a mental health defense in a criminal case, call (702) 825-7854 or contact us online to talk through your options. We're available 24/7.