Also known as:insanity defense · insanity defences · insanity defence · insanity plea
Written by attorneys — see sources below.
An affirmative defense in criminal proceedings that excuses liability when a mental disease or defect at the time of the offense caused the defendant to lack substantial capacity to appreciate the wrongfulness of the conduct or to conform the conduct to the requirements of law. The defense requires the defendant to give timely written notice to the government. The prosecution may not use post-Miranda silence to rebut the defense.
See Our Sources· 4 primary sources
Cases
Federal Rules
How its tested
Common Examples
6
Silence After Miranda Warnings
Danielle Dixon was arrested for assault and received Miranda warnings. She remained silent during questioning. At trial she raised an insanity defense based on schizophrenia. The prosecution sought to introduce her post-warning silence to show she understood her actions were wrongful. The court excluded the evidence.
Late Notice of Defense
Damian Decker planned to assert insanity after a violent episode tied to delusions. He filed written notice only after discovery closed and after receiving an unfavorable plea offer. The government moved to preclude the defense. The court denied leave to file late because no good cause was shown.
Access to Psychiatric Expert
Destiny Davis made a preliminary showing that her bipolar disorder would be central to an insanity claim at trial. The state refused to fund a defense psychiatrist. The court ordered the state to provide access so Davis could prepare and present the defense effectively.
Ake v. Oklahoma470 U.S. 68 (1985)
Late in 1979, Glen Burton Ake was arrested and charged with murdering a couple and wounding their two children. He was arraigned in the District Court for Canadian County, Oklahoma, in February 1980. His behavior at arraignment and in other prearraignment incidents at the jail was so bizarre that the trial judge, sua sponte, ordered him to be examined by a psychiatrist for the purpose of advising with the Court as to his impressions of whether the Defendant may need an extended period of mental observation.
The examining psychiatrist reported that at times Ake appeared to be frankly delusional and claimed to be the sword of vengeance of the Lord. He diagnosed Ake as a probable paranoid schizophrenic and recommended a prolonged psychiatric evaluation to determine whether Ake was competent to stand trial. In March 1980, Ake was committed to a state hospital to be examined with respect to his present sanity. On April 10, the chief forensic psychiatrist informed the court that Ake was not competent to stand trial. The court held a competency hearing at which a psychiatrist testified that Ake was a psychotic with a diagnosis of paranoid schizophrenia chronic with exacerbation, that he was dangerous, and that he required a maximum security facility. The court found Ake to be a mentally ill person in need of care and treatment and incompetent to stand trial, and ordered him committed to the state mental hospital.
Six weeks later, the chief forensic psychiatrist informed the court that Ake had become competent to stand trial while receiving 200 milligrams of Thorazine three times daily. At a pretrial conference in June, Ake's attorney informed the court that his client would raise an insanity defense. Counsel requested that a psychiatrist examine Ake with respect to his mental condition at the time of the offense or that the court provide funds for such an examination. The trial judge denied the motion. Ake was tried for two counts of murder in the first degree and two counts of shooting with intent to kill. At the guilt phase, defense counsel called the psychiatrists who had examined Ake at the state hospital, but none testified about his mental state at the time of the offense. The jury rejected the insanity defense and returned a verdict of guilty on all counts.
At the sentencing proceeding, the prosecutor relied on the testimony of the state psychiatrists that Ake was dangerous to society. Ake had no expert witness to rebut this testimony or to introduce evidence in mitigation. The jury sentenced Ake to death on each of the two murder counts and to 500 years' imprisonment on each of the two counts of shooting with intent to kill. On appeal, the Oklahoma Court of Criminal Appeals affirmed the convictions and sentences. The Supreme Court granted certiorari.
Product of Mental Disease
Daphne Doyle cut fences and released livestock onto a highway while fixated on delusions that the animals were government drones. Medical evidence showed her PTSD and dissociative episodes produced the conduct. The court applied the product test and acquitted her because the offense resulted from the mental disease.
Durham v. United States214 F.2d 862, 874–75 (D.C.Cir.1954)
Monte Durham was convicted of housebreaking by the District Court of the District of Columbia sitting without a jury. The prosecution proceeded on a charge arising from an incident on July 13, 1951, in which Durham was found in a house.
Durham's history included discharge from the Navy in 1945 at age seventeen following a psychiatric examination revealing a profound personality disorder rendering him unfit for service. In 1947 he pleaded guilty to violating the National Motor Theft Act and was placed on probation for one to three years. In January 1948, as a result of a conviction in the District of Columbia Municipal Court for passing bad checks, the District Court revoked his probation and he commenced service of his Motor Theft sentence. His conduct within the first few days in jail led to a lunacy inquiry in the Municipal Court where a jury found him to be of unsound mind. Upon commitment to St. Elizabeths he was diagnosed as suffering from 'psychosis with psychopathic personality.' He experienced multiple discharges and readmissions to St. Elizabeths between 1949 and 1951, including a conditional release in June 1950 that he violated, and a further lunacy finding in 1951.
Following the July 1951 housebreaking, Durham was indicted in October 1951 and adjudged of unsound mind based on psychiatrists' affidavits diagnosing psychosis with psychopathic personality. He underwent subshock insulin therapy during a six-month commitment ending in February 1953, after which Dr. Silk certified him mentally competent to stand trial and able to assist counsel.
At the ensuing trial, the prosecutor expressed a plan to allow Durham to raise an insanity defense on this charge. The court accepted waivers of jury trial and additional competency proceedings despite Durham's expressed desire for further hospitalization. Testimony included that of Durham's mother regarding his post-May 1951 behavior and a psychiatrist who examined him in September 1951 and opined on his mental condition around the time of the offense. The trial court found the defense of insanity not established under the prevailing standards.
The appeal reached the United States Court of Appeals for the District of Columbia Circuit.
Defendant Bears Burden
Dominic Drake raised insanity after a charged assault. The jurisdiction placed the burden of proving the defense on the defendant. Drake presented expert testimony on his schizophrenia. The jury found he failed to meet the burden and convicted him.
Patterson v. New York432 U.S. 197, 97 S.Ct. 2319, 53 L.Ed.2d 281
On December 27, 1970, Gordon Patterson shot and killed John Northrup in Glens Falls, New York. After a brief and unstable marriage, Patterson had become estranged from his wife Roberta. Roberta had resumed an association with Northrup, a neighbor to whom she had been engaged before her marriage to Patterson.
Patterson borrowed a rifle from an acquaintance and went to the residence of his father-in-law. There he observed his wife through a window in a state of semiundress in Northrup's presence. He entered the house and killed Northrup by shooting him twice in the head. Patterson was charged with second-degree murder.
At his jury trial in Warren County Court, Patterson raised the affirmative defense of extreme emotional disturbance and presented psychiatric evidence tending to show that he had been extremely emotionally disturbed when he killed Northrup. The jury was instructed that the prosecution had the burden of proving beyond a reasonable doubt each element of the crime of murder. The defendant had the burden of proving the affirmative defense by a preponderance of the evidence.
The jury convicted Patterson of second-degree murder. The Appellate Division affirmed the conviction. While appeal to the New York Court of Appeals was pending, this Court decided Mullaney v. Wilbur. The New York Court of Appeals nevertheless affirmed, distinguishing the Maine statute at issue in Mullaney and holding that New York's allocation of the burden of proof on the affirmative defense was consistent with due process. The United States Supreme Court granted certiorari limited to the question whether the burden of proof placed on the defendant by New York law is consistent with the Due Process Clause of the Fourteenth Amendment.
State Retains Element Burden
Daniel Diaz asserted insanity in a murder prosecution. The state proved every element of the offense beyond a reasonable doubt. Diaz bore the burden only on the insanity defense. The jury rejected the defense and returned a guilty verdict.
Mullaney v. Wilbur421 U.S. 684, 95 S.Ct. 1881, 44 L.Ed.2d 508 (1975)
In June 1966, a jury convicted Stillman E. Wilbur, Jr. of murder in a Maine state court. The prosecution introduced Wilbur's pretrial statement describing how he fatally assaulted Claude Hebert in Hebert's hotel room after a homosexual advance, together with circumstantial evidence of the killing. Although the defense presented no evidence at trial, it argued that Wilbur lacked criminal intent or that the homicide amounted at most to manslaughter because it occurred in the heat of passion provoked by the advance.
The trial court instructed the jury that an intentional and unlawful homicide would support a finding of malice aforethought unless the defendant proved by a fair preponderance of the evidence that he acted in the heat of passion on sudden provocation. After the jury twice returned for additional instructions on implied malice and the definition of heat of passion, it convicted Wilbur of murder. Wilbur appealed his conviction to the Maine Supreme Judicial Court, which upheld the trial court's instructions and affirmed the judgment.
Wilbur then filed a petition for a writ of habeas corpus in federal district court. The district court granted the petition, and the Court of Appeals for the First Circuit affirmed that decision. After the Maine Supreme Judicial Court issued its opinion in State v. Lafferty reaffirming its view of state law, the Supreme Court granted certiorari in this case and remanded to the Court of Appeals for reconsideration. On remand, that court again applied Winship, this time to the Maine law as construed by the Maine Supreme Judicial Court.
The Supreme Court granted certiorari a second time to consider the constitutional question presented by the Maine homicide law as applied to Wilbur's case.
5 common questions
Students Frequently Ask...
What must a defendant show under the traditional M'Naghten test to obtain an insanity acquittal?
The defendant must prove a disease of the mind caused a defect in reasoning that left the defendant unable to understand the nature and quality of the act or to know that the act was wrongful under societal standards. Personal moral belief that the conduct was justified is insufficient if the defendant retained capacity to recognize that society regards the conduct as wrong.
When must a defendant provide notice of an intent to rely on an insanity defense?
A defendant must notify the government in writing within the time for filing pretrial motions or at a later time set by the court and must file a copy with the clerk. Failure to provide timely notice bars reliance on the defense unless the court finds good cause for a late filing.
Supporting sources
May the prosecution use a defendant's post-Miranda silence to rebut an insanity defense?
No. The prosecution may not introduce post-Miranda silence as evidence to rebut or counter an insanity defense because such use violates the implicit assurance that silence carries no penalty.
Supporting sources
Who bears the burden of proving the insanity defense?
A state may constitutionally require the defendant to prove the affirmative defense of insanity by a preponderance of the evidence provided the prosecution retains the burden of proving every element of the offense beyond a reasonable doubt.
Supporting sources
When is a defendant entitled to state-funded psychiatric assistance for an insanity defense?
When the defendant makes a preliminary showing that sanity at the time of the offense is likely to be a significant factor at trial, the state must provide access to a psychiatrist to assist in preparing and presenting the defense.
Supporting sources
Criminal Law & ProcedureGeneral principles · ResponsibilityUBEFoundational