When someone with a serious mental illness is charged with a crime, one of the first questions families ask is whether the illness matters legally. In Massachusetts it can. A person is not guilty if, at the time of the offense, a mental disease or defect left them unable to appreciate that their conduct was wrong or unable to control it. This is what most people call the insanity defense.
This article explains the legal test, who has to prove what, how the issue is raised, and what really happens after a verdict of not guilty by reason of insanity.
What Is the Insanity Defense?
“Insanity defense is shorthand for a claim that the defendant lacked criminal responsibility. It does not mean the person is crazy” in the everyday sense. Massachusetts courts prefer the phrase “lack of criminal responsibility,” in part because calling it a defense” can mislead jurors about who has the burden of proof. The verdict itself is often called not guilty by reason of insanity,” or NGI.
The Massachusetts Test for Criminal Responsibility
Massachusetts adopted its test in Commonwealth v. McHoul, 352 Mass. 544 (1967), based on the Model Penal Code. A person lacks criminal responsibility if, at the time of the offense, they had a mental disease or defect and, as a result, lacked substantial capacity either:
- to appreciate the wrongfulness or criminality of their conduct; or
- to conform their conduct to the requirements of the law.
Either one is enough. The first prong asks whether the person knew or understood, in some meaningful way, that what they were doing was illegal or wrong. The second asks whether, even if they understood, the illness deprived them of the ability to obey the law. The test looks at the persons condition at the moment of the alleged crime, not before or after.
What Counts as a Mental Disease or Defect?
“Mental disease or defect” is a legal term, not a medical one. It does not have to fit a formal diagnosis, and the jury is not limited to the particular diagnosis an expert offers. It does not include an abnormality that shows itself only through repeated criminal or otherwise antisocial behavior. District Court Model Jury Instruction 9.200. Whether the defendant had a mental disease or defect is a question for the jury.
In practice, successful claims usually involve serious conditions, often with psychotic symptoms such as delusions or hallucinations, that substantially affected the person’s understanding or self-control at the time. Ordinary stress, anger, poor judgment, or everyday depression or anxiety are rarely enough on their own. But the question is never simply the name of the diagnosis. It is how the condition affected this person’s capacities at the time of the offense.
People sometimes cite the Department of Mental Health definition of mental illness: “a substantial disorder of thought, mood, perception, orientation, or memory which grossly impairs judgment, behavior, capacity to recognize reality or ability to meet the ordinary demands of life. 104 CMR 27.05. That definition governs involuntary civil commitment. It is relevant after an NGI verdict, but it is not the test for criminal responsibility.
Who Has the Burden of Proof?
The defendant never has to prove insanity. Once the issue is raised by any evidence that, if believed, might create a reasonable doubt about criminal responsibility, the Commonwealth must prove beyond a reasonable doubt that the defendant was criminally responsible. It can do that in one of two ways: by proving the defendant did not have a mental disease or defect at the time, or by proving that, even if they did, they still had substantial capacity both to appreciate the wrongfulness of their conduct and to conform it to the law. If the jury has a reasonable doubt, it must return a verdict of not guilty by reason of lack of criminal responsibility. Instruction 9.200.
Older cases speak of a “presumption of sanity.” That simply reflects the fact that most people are sane, so the issue does not arise until there is some evidence of mental illness. It does not shift the burden to the defendant. For more on the standard, see Proof Beyond a Reasonable Doubt.
Raising the Issue: Notice, Experts, and Court-Ordered Exams
In most cases, the defense retains a forensic psychiatrist or psychologist early. The expert reviews police reports and medical and psychiatric records, interviews the client, and forms an opinion about the client’s mental state at the time of the offense.
Under Massachusetts Rule of Criminal Procedure 14.4, a defendant who intends to raise their mental condition at trial, or to offer expert testimony about it, must give the prosecutor written notice, generally within the time for filing pretrial motions. The notice identifies the defense experts and whether they rely on the defendant’s own statements. If they do, the judge may order the defendant to be examined by an expert for the Commonwealth, with safeguards for the defendant’s privilege against self-incrimination. Separately, a judge who doubts a defendant’s competency or criminal responsibility may order an evaluation at any stage of the case, and may order a short hospital stay for further observation. G.L. c. 123, § 15. Many of these cases become a “battle of the experts.”
Expert testimony is helpful but not always required. The issue can be raised through the facts of the case, the Commonwealth’s own witnesses, lay witnesses who saw the person’s behavior, psychiatric records, or a combination. Commonwealth v. Mills, 400 Mass. 626 (1987), cited in Instruction 9.200. Failing to give notice under the rule may limit expert testimony, but it does not bar the defendant from raising the issue through lay evidence. See Do I Need an Expert Witness?.
Alcohol, Drugs, and Mental Illness
Voluntary intoxication by itself is not a mental disease or defect. If a person lacked the required capacity solely because they were drunk or high, they are criminally responsible.
It is different when alcohol or drugs trigger or intensify a mental illness the person already has. If the illness, activated or worsened by the substance, then caused the loss of capacity, the person is not criminally responsible, unless they knew or had reason to know that using the substance would have that effect. That knowledge is judged from the defendant’s point of view, including their mental capacity and past experience. And if the illness by itself was enough to cause the loss of capacity, the person is not criminally responsible regardless of any drug or alcohol use. Commonwealth v. Berry, 457 Mass. 602 (2010); Commonwealth v. DiPadova, 460 Mass. 424 (2011); Instruction 9.200. See also Intoxication With Alcohol or Drugs.
Competency to Stand Trial vs. Criminal Responsibility
These two ideas are often confused. Competency looks at the present: can the defendant understand the court proceedings and help their lawyer with the defense right now? Criminal responsibility looks at the past: what was the defendant’s mental state at the time of the alleged crime? A person can be competent to stand trial today and still have lacked criminal responsibility when the offense occurred, and the reverse is also possible. A court may order an examination on either question, or both.
What Happens After a Not Guilty by Reason of Insanity Verdict?
An NGI verdict does not mean the person simply walks out of the courtroom. Under G.L. c. 123, § 16:
- The judge may order the person hospitalized for up to 40 days for observation and examination, at a mental health facility or, for a man who requires strict security, at Bridgewater State Hospital.
- During that period, or within 60 days after the verdict, the district attorney or the facility may petition the court to commit the person.
- The court may order commitment only if it finds the person is mentally ill and that discharge would create a likelihood of serious harm. The first commitment order lasts 6 months.
- After that, the person may be recommitted for one-year periods, with a court review each time. There is no limit on the number of renewals, and commitment is not tied to the maximum sentence for the original charge.
If the person is no longer mentally ill and dangerous, they must be discharged. The district attorney is notified and may be heard, but the final decision to recommit or release is always made by a judge. When the defense is fairly raised, the defendant is entitled on request to have the jury told what happens after an NGI verdict. Commonwealth v. Mutina, 366 Mass. 810 (1975).
There are record consequences too. Findings of not guilty by reason of insanity appear on criminal record checks in the same categories as convictions. G.L. c. 6, § 172. See What Is in a Massachusetts Criminal Record?.
Mental Impairment Short of Insanity
Even when the full defense is not available, mental illness can still matter. For crimes that require a specific intent, the jury may consider evidence of the defendant’s mental condition in deciding whether the Commonwealth proved that intent. If the condition left the person incapable of forming the required intent, they must be acquitted of that charge. Instruction 9.220. Read more in Mental Impairment Short of Insanity, and see Criminal Intent Explained and Transferred Intent.
Practical Considerations for Defendants and Families
Raising lack of criminal responsibility is a major strategic decision. It usually calls for:
- Retaining a qualified forensic expert early.
- Collecting and preserving medical, psychiatric, school, and treatment records, and identifying people who observed the persons behavior around the time of the offense.
- Careful timing of the Rule 14.4 notice and any disclosures to the Commonwealth.
- A realistic assessment of the clinical evidence and of how a jury is likely to view it.
- A clear understanding of the consequences of success, which may mean an extended hospital commitment rather than a fixed sentence.
Frequently Asked Questions
Is the insanity defense easy to win in Massachusetts?
No. Successful claims are relatively uncommon. The evidence has to show a serious condition that substantially impaired the persons capacity at the time, and jurors are often skeptical. But because the Commonwealth carries the burden once the issue is raised, a well-supported claim can succeed.
Does a successful claim mean the person goes free?
Not necessarily. The person may be hospitalized for observation and then committed for as long as they remain mentally ill and dangerous, with a judge reviewing the commitment at each renewal.
Can depression or anxiety alone support the defense?
Rarely. The label matters less than the effect. The question is whether the condition substantially impaired the person’s ability to appreciate wrongfulness or to control their conduct at the time.
Who decides the issue, the judge or the jury?
In a jury trial, the jury decides whether the Commonwealth has proved criminal responsibility beyond a reasonable doubt. In a bench trial, the judge decides.
Talk to a Massachusetts Criminal Defense Lawyer
When mental illness is part of a criminal case, early decisions about experts, records, and strategy can shape the outcome. If you or a family member is facing charges, the Law Office of William J. Barabino in Medford can review the situation and explain whether lack of criminal responsibility, mental impairment, or another approach fits the facts. Attorney Barabino has over 23 years of experience in criminal defense and represents clients throughout Greater Boston.
Call 781-393-5900 for a confidential consultation.
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Disclaimer
This article is for general educational purposes only and is not legal advice. The law on criminal responsibility and mental health commitment is complex and can change through new statutes, rules, and court decisions. Every case turns on its own facts. Reading this page does not create an attorney-client relationship. If you or a family member is facing a criminal charge involving mental health issues, consult a licensed Massachusetts criminal defense attorney about your situation.
