Report to Minnesota Legislature: Mentally Ill Criminals and the Insanity Defense (excerpt)


This report is about how the criminal justice system deals with people who have a severe mental illness. Mental illness is a conundrum for the courts. People with schizophrenia, for example, have a profound loss of ability to think, plan, and make decisions because their brains don't work correctly. Some may have a delusion that their life is in danger and commit a crime to protect themselves. Others may hear over-powering voices commanding them to do something wrong. Are such people competent to stand trial or agree to a plea bargain? Do they meet the legal standard of intent to commit a crime? Does their illness excuse them or mitigate the severity ofpunishment? What should happen to them if convicted, or if not convicted?

Because no clear answers exist to these questions, states have taken different legal paths with mental illness. Minnesota, for instance, uses a legal test for judging whether someone is not guilty by reason of insanity that came from a 19th century British case. Other states, however, have adopted newer tests for insanity or have added the verdict "guilty but mentally ill." Some states allow a defendant to claim mental illness as a mitigating factor; others do not. A few states have abolished the insanity defense. Usually these changes reflect shifting public sentiments about whether mentally ill criminals should be punished or treated for their illness, and about how best to protect the public from mentally ill criminals.

New discoveries about mental illness might also cause us to re-examine the treatment of mentally ill people in criminal justice. Until recently, the biological basis of serious mental illness was virtually unknown. Now, high-tech brain scans show the exact areas of a sick brain that are not working properly, and biochemists have discovered some of the chemical pathways in the brain that malfunction in mental illness. These discoveries have increased public awareness ofmental illness and helped reduce the social stigma that is often attached to those who suffer these illnesses. 

Severe Mental Illness

Authorities distinguish severe or serious mental illnesses, which are physical diseases of the brain, from less serious mental conditions that are usually psychological but not physical in origin.! Serious mental illness includes schizophrenia, bipolar (manic- depressive) illness, and major depression. Obsessive-compulsive disorder and panic attacks are often added to the list. Together, these illnesses are more common than cancer or heart disease and, over a lifetime, affect one in five families. About 20 percent of the nation's hospital beds are taken by people with a mental illness. Severe brain disorders have both hereditary and environmental causes that are not yet fully understood.

Serious mental illness does not include mental retardation, hyperactivity, multiple personality, personality or character disorder, psychopathic personality, sexual psychopathology, pedophilia, addiction, or similar conditions, although research points increasingly to the likelihood that some of these, too, are related to brain disorders.

Serious mental illness disrupts a person's ability to think, feel, and relate to other people and the physical environment. Many people with a severe mental illness lose their jobs, become estranged from their families, are homeless, or commit suicide. About 160,000 people with severe mental illnesses are in the nation's jails and prisons.

Schizophrenia is the most chronic and disabling mental illness, affecting 1 percent of the population. It usually strikes people in their late teens or early twenties, although victims may have subtle signs ofbrain dysfunction in childhood. Typical symptoms are hallucinations, delusions, and bizarre thinking, collectively referred to as psychosis. People with the illness may believe that their thoughts are under control of someone else or coming from outside their head. Poor brain functioning also causes a breakdown of social relationships, poor communication skills, and lack of motivation. Schizophrenia has different subtypes; one is paranoid schizophrenia, in which the victim has intense fears or feelings of persecution accompanying hallucinations. Although many people with schizophrenia are helped by drug therapy and social assistance, few recover from the disease.

Bipolar illness and depression affect a person's mood more than thinking ability. In bipolar illness, a person's mood cycles between extreme depression, normal mood, and extreme euphoria or mania. In the manic stage a person may have grandiose delusions or psychotic thought processes similar to those of schizophrenia and may abuse illegal drugs or alcohol. At the other extreme, a person who is extremely depressed may feel life is hopeless and have difficulty concentrating or making decisions; suicide is a strong possibility. Mood disorders can usually be treated successfully with drugs and electroconvulsive therapy, but the illness may return intermittently.

Mental Illness and Crime

Crimes by mentally ill people are sometimes very sensational, which may give the public the misperception that mentally ill people often commit violent crimes. Researchers have closely examined the link between mental illness and violent crime. They have found that most people who commit violent crimes are not mentally ill and most mentally ill people do not commit crimes. One study found that about 3 percent of the variation in violent crime in the United States is related to mental illness.

In general, mentally ill people are more likely to be victims of violent crime than perpetrators. But research has pointed to a small group of people with severe mental illness who are at higher risk for violent behavior.  People with psychoses - bizarre thinking, hallucinations, and delusions - as found in schizophrenia and, less often, in mood disorders, are more likely to commit violent crimes than people with no mental disorder. This has been reported in many research studies

A connection with violence also applies to people with some neurological brain diseases, such as Huntington's chorea, and to people who have had head injuries that damaged the brain.

A recent study of mentally ill people looked at their use of medication and alcohol in relation to violence. Results showed that when mentally ill people stop taking their medicine and abuse alcohol or illegal drugs, they are more likely to be violent. Violent behavior is also more likely among people with paranoia who hear command voices telling them to kill someone, or who believe their mind is dominated by forces beyond their control. The victims of mentally ill people are often members of their own family.

Frequency of Insanity Pleas and Acquittals

For centuries the law has encompassed the widely held belief that some people are too mentally deranged to know what they are doing and, therefore, cannot be held morally responsible for a crime. This principle came from English common law, which presumed that an illegal act was not a crime unless performed with criminal intent. In a criminal trial, a mentally ill person might be found not guilty by reason of insanity, despite proof that the person had committed a crime.

Insanity pleas and acquittals are relatively uncommon. An eight-state study of 581,000 indictments found 8,979 insanity pleas - a rate of 1.5 percent,6 A different study of insanity cases in four states (California, Georgia, Montana, and New York) showed that of 586,000 felony indictments, only 5,300 (0.9%) had a plea of insanity by the defendant,? And of the 5,300 insanity pleas, there were 1,385 acquittals by reason of insanity - 0.23 percent of indictments and 26 percent of insanity pleas. A study of adult defendants represented by the Public Defender's office in New Jersey found 52 insanity pleas for 32,000 defendants (less than 0.2%) and of the 52 cases, 15 were successful. 

The connection between serious mental illness and successful insanity pleas is well documented.  The eight-state study of almost 2,600 criminal defendants who were found not guilty by reason of insanity (NGRl) reported that 68 percent had schizophrenia and 16 percent had a severe mood disorder - a total of 84 percent with a severe mental illness.  The others were mentally retarded (5%) had another illness (5%), a  personality disorder (3.5%), or were chemically dependent. The crimes they had been charged with were murder (150/0), physical assault (38%), other violent crimes (12%), robbery (7%), property crimes (18%), and other minor crimes (10%).

Mentall Illness in Prisons

A report by the federal Bureau of Justice Statistics estimated that 10 percent of inmates in the nation's state prisons and 10 percent of those in local jails currently have a mental illness; another 6 percent have previously had a mental condition. These data are based on self-reporting by inmates in a national survey. About 19 percent of inmates reported that they have taken a prescribed medication for a "mental or emotional condition." Mental illness was reported more often by female prisoners than males, and more often by white prisoners than other races. Alcohol and drug use were more strongly associated with mentally ill inmates than others, and nearly 6 of 10 mentally ill inmates reported that they were under the influence of alcohol or drugs at the time of their current offense. Mentally ill inmates in state prisons serve longer than average sentences because they are more frequently involved in fights and have more disciplinary problems than other inmates.

Legal Dimensions of Menta/Illness and Crime

The large numbers of mentally ill inmates in jails and prisons show that the legal concept of "insanity" is not the same as a medical diagnosis of mental illness, such as schizophrenia or paranoia. In fact, few people who are mentally ill meet t4e legal standard of insanity. The courts use one of several legal tests - not medical tests - to determine whether people meet the standard of insanity that would excuse them from guilt for a crime.



We first review the most common tests for insanity, then other dimensions of legal process.

McNaughtan test

In 1843 Daniel McNaughtan shot and killed the secretary of the British Prime Minister by mistake while intending to kill the Prime Minister. At trial, McNaughtan was found "not guilty, on the ground of insanity." Public outcry and royal concern about the acquittal led a panel ofjustices to establish a standard for insanity, which is still used by British courts. The test was meant to be used by a jury after hearing medical testimony from prosecution and defense experts. Under this rule a defendant was presumed sane unless the defense proved that:

"At the time of committing the act, the party accused was laboring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing or, ifhe did know it, that he did not know what he was doing was wrong."

About half of American states use the test [or a modified version, as in New York]. Notice, however, that it does not excuse mentally ill people who knew what they did was wrong but were unable to control their actions. To allow for this possibility, several states have added an exculpatory provision for a person who could not contro


American Law Institute test

In 1972 the Court of Appeals for the District of Columbia endorsed a Model Penal Code standard, which the American Law Institute had proposed in the 1950s. Under the ALI test,

A person is not responsible for criminal conduct if at the time of such conduct as a result of mental disease or defect he lacks substantial capacity either to appreciate the criminality (wrongfulness) of his conduct or to conform his conduct to the requirements of the law.

The ALI test is less stringent than McNaughtan because it does not require a total lack of self-control or inability to know right from wrong, but only that someone with mental illness "lacks substantial capacity" to act and reason normally. The ALI test is used in about 20 states, and it was used in federal courts until 1984, when a more stringent test was adopted.

Appreciation test

In 1984 the appreciation test was made law in all federal courts by act of Congress.  A few states have adopted similar laws. These changes were largely a response to public dismay when John Hinckley was found NGRI after his attempted assassination of President Reagan. Federallaw requires that a defendant prove by clear and convincing evidence that:

"At the time of the commission of the acts constituting the offense, the defendant, as a result of a severe mental disease or defect, was unable to appreciate the nature and quality or the wrongfulness of his acts."

At the time of the commission of the acts constituting the offense, the defendant, as a result of a severe mental disease or defect, was unable to appreciate the nature and quality or the wrongfulness of his acts.   The requirement of "unable to appreciate" is tougher than ALI's "lacks substantial capacity."

No test

Three states have abolished the insanity defense: Utah, Montana, and Idaho.  [Note, more states have abolished the test since then]. In these states, however, defendants can offer evidence at trial that they lacked the mental capacity to form the intent to commit the crime they are charged with. The prosecution must rebut this claim beyond a reasonable doubt.

Civil commitment test

Sometimes mentally ill persons who commit crimes go through the civil commitment process instead of being prosecuted. This option might be pursued by the county attorney after an arrest for a misdemeanor, or a mentally ill person might be diverted into the medical system without being arrested or charged for the crime. Mentally ill persons can be committed to supervision and care by the state in a state hospital when they are a danger to themselves or others. (Commitment is also possible for mentally ill persons who are unable to care for themselves.) Behavior that meets the test of dangerousness for civil commitment overlaps with behavior that might be prosecuted as a criminal offense.

Several decades ago, the standards for civil commitment were less stringent than today, and people with a severe mental illness were often committed to care in a state hospital before they would have met today's test of dangerousness. Now, restrictive commitment laws make it more likely that people with severe mental illness are caught up in the criminal justice system. This is a well recognized and often debated national phenomenon.