Following tragic mass shootings such as the one that unfolded in Newtown, Connecticut, it is natural to try to “make sense” of the events. The process of “making sense” and understanding the underlying causes is part of the healing process. It also gives hope to society that if we were able to address the causes of the tragedy, we could prevent future tragedies. It is not unexpected that mental illness is often invoked as a possible reason for mass shootings. After all, the slaying of fellow human beings seems so far removed from what we consider normal human behavior. Since mental illness directly affects human behavior, it seems like the most straightforward explanation for a mass shooting. It is surmised that the mental illness severely impairs the decision-making capacity and perceptions of the afflicted person so that he or she is prone to acting out in a violent manner and causing great harm to others. Once evidence for “mental illness” in a shooter is found, one may also be tempted to stop looking for other factors that may have caused the tragedy. The nebulous expression “mental illness” can appear like a convenient catch-all explanation that requires no further investigation, because the behavior of a “mentally ill” person might be beyond comprehension.
The problem with this convenient explanation is that “mental illness” is not a homogeneous entity. There are many different types of mental illness, and specific psychiatric disorders, such as major depression, anxiety disorder or schizophrenia represent a broad spectrum of disease. These illnesses do not only vary in their severity from patient to patient, but even within a single patient, mental illnesses vary over time in severity. Just because someone carries the diagnosis of schizophrenia does not mean that the patient will continuously have severe manifestations of the disease. Some patients may show signs of withdrawal and introversion, others may act out with aggressive behavior. Making a direct causal link between a person’s diagnosis of mental illness and their violent behavior requires a careful psychiatric examination of that individual patient, as well as other circumstances, such as recent events in their lives or possible substance abuse.
When shooters kill themselves after the murders they commit, it is impossible to perform such a psychiatric examination and all that one can go by are prior medical records, but it becomes extremely difficult to retrospectively construct cause-effect relationships. In the case of Adam Lanza, the media and the public do not have access to his medical records. However, soon after the shooting, there was frequent mention in the media that Lanza had been diagnosed with either Asperger syndrome, autism or a personality disorder and potential links between these diagnoses and the shooting were implied. Without carefully perusing his medical records, it is difficult to assess whether these diagnoses were accurate, how severe his symptoms were and how they were being treated. To make matters worse, some newspapers and websites have resorted to generating narratives about Adam Lanza’s behavior and mental health based on subjective and anecdotal experiences of class-mates, family friends and in perhaps the most ridiculous case, Lanza’s hair stylist. Snippets of subjective information regarding odd behaviors exhibited by Lanza have been offered to readers and viewers so that they can perform an armchair evaluation of Lanza’s mental health from afar and search for potential clues in his past that might point to why he went on a shooting rampage. Needless to say, this form of armchair analysis is fraught with error.
It is difficult enough to diagnose a patient during a face-to-face evaluation and then try to make causal links between the symptoms and the observed pathology. In the setting of cardiovascular disease, for example, the healthcare professional has access to blood tests which accurately measure cholesterol levels or biomarkers of heart disease, angiograms that generate images of the coronary arteries and even ultrasound images of the heart (echocardiograms) that can rather accurately assess the strength of the heart. Despite all of these objective measurements, it requires a careful and extensive discussion with the patient to understand whether his shortness of breath is truly linked to his heart disease or whether it might be related to other factors. Someone might have mild heart disease by objective testing, but the shortness of breath he experiences when trying to walk up the stairs may be due to months of physical inactivity and not due to his mild heart disease.
In psychiatry, making diagnoses and causally linking symptoms and signs to mental illness is even more difficult, because there are fewer objective tests available. There are, as of now, no CT-Scans or blood tests that can accurately and consistently diagnose a mental illness such as depression. There are numerous reports of documented abnormalities of brain imaging observed in patients with mental illness, but their reliability and their ability to predict specific outcomes of the respective diseases remains unclear. The mental health professional has to primarily rely on subjective reports of the patient and the patient’s caregivers or family members in order to arrive at a diagnosis. In the case of Adam Lanza, who killed himself as well as his mother, all one can go by are his most recent mental health evaluations, which could provide a diagnosis, but may still not reliably explain his killing spree. Retrospective evaluations of his mental health by former class-mates, hair stylists or family members are of little help. Comments on the past behavior of a mass shooter will invariably present a biased and subjective view of the past, colored by the knowledge of the terrible shooting. Incidents of “odd behaviors” will be remembered, without objectively assessing how common these behaviors were in other people who did not go on to become mass shooters.
An article written by Liza Long with the sensationalist title “I Am Adam Lanza’s Mother” was widely circulated after the shooting. Long was obviously not the mother of Adam Lanza, and merely took advantage of the opportunity to describe her frustration with the mental health care system and her heart-wrenching struggles with the mental health of her son who was prone to violent outbursts. In addition to violating the privacy of her son and making him a likely target of future prejudice and humiliation, Long implied that the observed violent outbursts she had seen in her son indicated that he might become a mass shooter like Adam Lanza. Long, like the rest of the public, had no access to Lanza’s medical records, did not know whether Lanza had been diagnosed with the same illnesses as her own son and whether Lanza had exhibited the same behaviors. Nevertheless, Long’s emotional story and the sensationalist title of her article caught on, and many readers may have accepted her story as a proof of the link between certain forms of mental illness and predisposition to becoming a mass shooter.
Instead of relying on retrospective analyses and anecdotes, it may be more helpful to review the scientific literature on the purported link between mental illness and violence.
The link between mental illness and violence
There is a widespread notion that mental illness causes violent behavior, but the scientific evidence for this presumed link is not that solid. “Mental illness” is a very heterogeneous term, comprising a wide range of disorders and degrees of severity for each disorder, so many studies that have tried to establish a link between “mental illness” and violence have focused on the more severe manifestations of mental illness. The 1998 land-mark study “Violence by People Discharged From Acute Psychiatric Inpatient Facilities and by Others in the Same Neighborhoods” by Henry Steadman and colleagues was published in the highly cited psychiatry journal Archives of General Psychiatry and focused on patients whose mental illness was severe enough to require hospitalization. The study followed patients for one year after they were released from the acute psychiatric inpatient units, and assessed how likely they were to engage in violence. At one of the sites (Pittsburgh), the researchers also compared the likelihood of the psychiatric patients to engage in violence with that of other residents of the same neighborhood. Steadman and colleagues found that there was a higher rate of violence observed in psychiatric patients, this was associated with the higher rate of substance abuse. Psychiatric patients without substance abuse had the same rate of violence as other residents of the neighborhood without substance abuse.
The recent large-scale study “The Intricate Link Between Violence and Mental Disorder” was published in the Archives of General Psychiatry by Elbogen and Johnson in 2009 and also found that severe mental illness by itself was not a strong predictor of violence. Instead, future violence was more closely associated with a history of past violence, substance abuse or contextual factors, such as unemployment or a recent divorce. A 2009 meta-analysis by Fazel and colleagues was published in PLOS Medicine and reviewed major studies that had investigated the potential link between schizophrenia and violence. The authors found an increased risk of violence and homicide in patients with schizophrenia, but this was again primarily due to the higher rates of substance abuse in the patient population. The risk of homicide in individuals with schizophrenia was 0.3%, and the risk of homicide was also 0.3% in people with a history of substance abuse. All of the studies noted a great degree of variability in terms of violence, again reminding us that mental illnesses are very heterogeneous diseases. An individual diagnosed with “schizophrenia” is not necessarily at higher risk for engaging in violent behavior. One also has to assess their specific context, their past history of violence, their social circumstances and especially their degree of substance abuse, which can refer to alcohol abuse or alcohol dependence as well as the abuse of illegal substances such as cocaine. The data on whether Asperger syndrome, one of the conditions that Adam Lanza is said to have been diagnosed with, is far sparser. Stål Bjørkly recently reviewed the studies in this area and found that there has been no systematic research in this field. The hypothesized link between Asperger syndrome and violence is based on just a few studies, mostly dealing with case reports of selected incidents.
It is quite noteworthy that multiple large-scale studies investigating the association between mental illness and violence have come up with the same conclusion: Patients with mental illnesses may be at greater risk for engaging in violence, but this appears to be primarily linked to concomitant substance abuse. In the absence of substance abuse, mental illness by itself does not significantly increase the likelihood of engaging in violence. Richard Friedman summarized it best in an article for the New England Journal of Medicine:
The challenge for medical practitioners is to remain aware that some of their psychiatric patients do in fact pose a small risk of violence, while not losing sight of the larger perspective — that most people who are violent are not mentally ill, and most people who are mentally ill are not violent.
Human behavior and mental illness
One rarely encounters armchair diagnoses in cardiovascular disease, neurologic disease or cancer. Journalists do not usually interview relatives or friends of cancer patients to ascertain whether there had been early signs of the cancer that had been missed before the definitive diagnosis was made or a patient died of cancer. If medical details about public persona are disclosed, such as for example the heart disease in the case of former vice-president Cheney, journalists and TV viewers or readers without medical expertise rarely offer their own opinion whether the diagnosis of cardiovascular disease was correct and how the patient should be treated. There were no interviews with other cardiovascular patients regarding their own personal history of heart disease and they were also not asked to comment on how they felt Cheney was being treated. In the case of the 2012 US meningitis outbreak, which resulted in the death of at least 35 people, many questions were raised in the media regarding the underlying causes and there was understandable concern about how to contain the outbreak and address underlying causes, but the advice was usually sought from experts in infectious disease.
When it comes to mental illness, on the other hand, nearly everyone with access to the media seems to think they are an expert on mental health and one finds a multitude of opinions on the efficacy of psychoactive medications, whether or not psychiatric patients should be institutionalized and warning signs that lead up to violent behavior. There are many potential reasons for why non-experts feel justified in commenting on mental illness, but remain reticent to offer their opinion on cardiovascular disease, cancer or infectious disease. One reason is the subject matter of psychiatry. As humans, we often define ourselves by our thoughts, emotions and behaviors – and psychiatry primarily concerns itself with thoughts, emotions and behaviors. Our personal experiences may embolden us to offer our opinions on mental health, even though we have not had any formal training in mental health.
The psychiatric profession itself may have also contributed to this phenomenon by blurring the boundaries between true mental illness and the broad spectrum of human behavior. The criteria for mental illness have been broadened to such an extent that according to recent studies, nearly half of all Americans will meet the criteria for a mental illness by the time they have reached the age of 75. There is considerable debate among psychiatrists about the potential for over-diagnosis of mental illness and what the consequences of such over-diagnoses might be. The labeling of mildly “abnormal” behaviors as mental illnesses not only results in the over-prescription of psychoactive medications, but it may also take away mental health resources from patients with truly disabling forms of mental illness. For example, the upcoming edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM – which establishes the diagnostic criteria for each mental disorder) will remove the bereavement exemption for the diagnosis of depression. This means that people suffering from severe grief after the death of their loved ones, such as the parents of the children that were murdered in Newtown, could conceivably be diagnosed with the mental disorder “Major Depression”.
Romanticizing and vilifying mental illness
The topic of mental illness also lends itself to sensationalism. Occasionally, mental illness is romanticized, such as the idea that mental illness somehow fosters creativity for which there is little scientific evidence. More often, however, patients with mental illness are vilified. Broad generalizations are made and violent tendencies or criminal behaviors are ascribed to patients, without taking into account the heterogeneity of mental illness. Wayne LaPierre of the National Rifle Association (NRA) recently called for the creation of an “active national database of the mentally ill” and on a subsequent event, LaPierre referred to mentally ill patients as “monsters” and “lunatics”. Such sensationalist rants may make for good publicity, but they also help further undermine an objective discussion about mental health. Especially the call for a national database of mentally ill people comes seems somewhat counter-intuitive since the NRA has often portrayed itself as a defender of personal liberty and privacy. Are organizations such as the NRA aware of the fact that nearly half of all Americans will at some point in their life qualify for mental illness diagnoses and would have to be registered in such a database? Who would have access to such a database? For what purposes would the database be used? Would everyone listed in the database be barred from buying guns? How about household members living with a patient who has been diagnosed with a mental illness? Would these household members also be barred from buying guns? If indeed all patients with at least one psychiatric diagnosis were registered in a national database and if they and their household members were barred from owning guns, nearly all US households would probably become gun-free. If one were to follow along the logic of the NRA, one might even have to generate a national database of people with a history of substance abuse or a past history of violence, since the above-mentioned research showed that substance abuse and past history of violence may be even stronger predictors of future violence than mental illness.
When it comes to reporting about mental illness it is especially important to avoid the pitfalls of sensationalism. Mental illness should be neither romanticized nor vilified. Potential links between mental illness and behaviors such as violence should always be made in the context of the existing medical and scientific literature and one should avoid generalizations and pronouncements based on occasional anecdotes. Journalists and mental health professionals need to help ensure the accuracy and objectivity of analyses regarding the mental health of individuals as well as specific mental illnesses. It never hurts to have a discussion about mental health. There is clearly a need for the improvement of the mental health infrastructure and for the development of better therapies for psychiatric disease, but this discussion should be based on facts and not on myths.
Image Credit: Brain of MRI scan data for child onset schizophrenia showing areas of brain growth and loss of tissue via NIMH