Mass Shootings and Mental Illness

Abstract

Mass shootings understandably create outpourings of public horror and outrage. Nevertheless, and contrary to common media depictions and the general public’s beliefs, mass shootings are extremely rare events. These tragedies are influenced by multiple complex factors, many of which are still poorly understood. However, the lay public and the media typically assume that the perpetrator has a mental illness and that the mental illness is the cause of these highly violent acts of horrific desperation. Although some mass shooters are found to have a history of psychiatric illness, no reliable research has suggested that a majority of perpetrators are primarily influenced by serious mental illness as opposed to, for example, psychological turmoil flowing from other sources. As a result, debate on how to prevent mass shootings has focused heavily on issues that are 1) highly politicized, 2) grossly oversimplified, and 3) unlikely to result in productive solutions.

In this chapter, we discuss the existing research, limited though it may be, on mass shootings and then examine the nature of the link between gun violence and mental illness. We consider the value of gun laws focusing on mental illness, with attention to their potential efficacy in preventing future mass shootings. We conclude by proposing that instead of the focus on mental illness, increased attention should be paid to sociocultural factors associated with mass shootings and exploring other interventions and areas for further research.

Full text

81
4
Mass Shootings and
Mental Illness
James L. Knoll IV, M.D.
George D. Annas, M.D., M.P.H.
Common Misperceptions
Mass shootings by people with serious mental illness represent the
most significant relationship between gun violence and mental illness.
People with serious mental illness should be considered dangerous.
Gun laws focusing on people with mental illness or with a psychiatric
diagnosis can effectively prevent mass shootings.
Gun laws focusing on people with mental illness or a psychiatric diag-
nosis are reasonable, even if they add to the stigma already associated
with mental illness.
Evidence-Based Facts
Mass shootings by people with serious mental illness represent less
than 1% of all yearly gun-related homicides. In contrast, deaths by
suicide using firearms account for the majority of yearly gun-related
deaths.
The overall contribution of people with serious mental illness to vio-
lent crimes is only about 3%. When these crimes are examined in de-
tail, an even smaller percentage of them are found to involve firearms.
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

82 GUN VIOLENCE AND MENTAL ILLNESS
Laws intended to reduce gun violence that focus on a population rep-
resenting less than 3% of all gun violence will be extremely low yield,
ineffective, and wasteful of scarce resources. Perpetrators of mass
shootings are unlikely to have a history of involuntary psychiatric hos-
pitalization. Thus, databases intended to restrict access to guns and
established by guns laws that broadly target people with mental ill-
ness will not capture this group of individuals.
Gun restriction laws focusing on people with mental illness perpetu-
ate the myth that mental illness leads to violence, as well as the mis-
perception that gun violence and mental illness are strongly linked.
Stigma represents a major barrier to access and treatment of mental
illness, which in turn increases the public health burden.
Mass shootings understandably create outpourings of public horror and
outrage. Nevertheless, and contrary to common media depictions and the gen-
eral public’s beliefs, mass shootings are extremely rare events. These tragedies
are influenced by multiple complex factors, many of which are still poorly un-
derstood. However, the lay public and the media typically assume that the perpe-
trator has a mental illness and that the mental illness is the cause of these highly
violent acts of horrific desperation. Although some mass shooters are found to
have a history of psychiatric illness, no reliable research has suggested that a
majority of perpetrators are primarily influenced by serious mental illness as
opposed to, for example, psychological turmoil flowing from other sources. As a
result, debate on how to prevent mass shootings has focused heavily on issues
that are 1) highly politicized, 2) grossly oversimplified, and 3) unlikely to result in
productive solutions.
In this chapter, we discuss the existing research, limited though it may be, on
mass shootings and then examine the nature of the link between gun violence
and mental illness. We consider the value of gun laws focusing on mental illness,
with attention to their potential efficacy in preventing future mass shootings. We
conclude by proposing that instead of the focus on mental illness, increased at-
tention should be paid to sociocultural factors associated with mass shootings
and exploring other interventions and areas for further research.
MASS MURDER IN THE UNITED STATES
Because of frequent and sensational media coverage, it may appear that the era
of mass shootings began in 1966, atop the tower at the University of Texas in
Austin, and became a part of American life in subsequent decades (Associated
Press 2007). However, cases of mass murder, of which mass shootings are a sub-
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

Mass Shootings and Mental Illness 83
set, have been recorded over time long before mass shootings captured public
attention. For example, in the Bath school disaster of 1927, to this day the dead-
liest mass murder in a school in United States history, one man killed 38 Mich-
igan elementary school children and 6 adults and injured at least 58 other
people.
The farmer who perpetrated these attacks had run into financial trouble. His
wife was seriously ill with tuberculosis. He reportedly became angry after an in-
crease in taxes and losing an election in which he had run for town clerk. He first
killed his wife, then firebombed his farm, and then detonated explosives in the
Bath Consolidated School, before committing suicide by detonating a final explo-
sion in his truck. Like many modern-day mass murderers, he left a final com-
munication. Stenciled and painted on a board outside his property, his message
read, “Criminals are made, not born”—a statement suggestive of externalization
of blame and long-held grievance. Many “premodern” cases of mass murder often
involved a depressed and angry male who killed his family and then himself. Such
cases did not capture much media attention because they were regarded primar-
ily as “family business” and were “too close for comfort” (Dietz 1986, p. 481). In
contrast, mass shootings beginning in the 1990s and covered intensely by the me-
dia appeared to be a different type of violence, at least in the eyes of the public.
Heavily armed individuals who had meticulously planned a public massacre in
which they intended to spread as much destruction as possible and then kill
themselves seemed a new phenomenon. Compared with depressed and despair-
ing familicide-suicides, these “modern” cases seemed distant enough from the av-
erage person’s experience to capture the public’s attention with morbid fascination
over prolonged periods of time.
Mass shootings cause endless public speculation regarding causes and mo-
tives. However, high-profile cases of mass shootings, which typically receive the
most intense media coverage, are in fact the least representative of mass killings.
In reality, such rare cases are the result of many complex factors. Nevertheless,
the news media have heavily influenced the public’s perception of mass murders
(Duwe 2005), offering simplified explanations that assume the perpetrator is ei-
ther “mad or bad.” After all, who but a madman would execute innocent people
in broad daylight, while planning to commit suicide or be killed by police?
Such simplistic explanations are easier for the media to report, as well as eas-
ier for the public to accept. Nevertheless, these explanations are often inaccurate
and based on little or no evidence. In addition, they stoke the political fires sur-
rounding debates concerning regulation of firearms while providing no construc-
tive suggestions to prevent future tragedies. Psychiatric illness, although present
in some mass murderers and mass shooters, is far from the most significant or
consistent finding from attempts to investigate the nature of these deeply trou-
bling events.
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

84 GUN VIOLENCE AND MENTAL ILLNESS
MASS SHOOTINGS: WHAT IS KNOWN
A mass shooting is a specific type of mass murder. Mass murder is defined as the
killing of three or more victims at one location within one event (Burgess 2006).
The motives of mass murderers typically involve the desire to kill as many as pos-
sible; such a motive does not limit a perpetrator to a particular means (e.g., guns,
bombs, arson). Those who commit mass murder may use more than one means to
achieve this goal. For example, the mass shooting at an Aurora, Colorado, movie
theater in 2012 involved a perpetrator who also booby-trapped his apartment
with multiple bombs in an attempt to kill more people in addition to those killed
in the shooting. The Norwegian man who committed a mass shooting on Utøya
in 2011 set off a bomb in Oslo prior to the shooting. Nevertheless, guns are an
efficient and often accessible means to carry out the goal of killing multiple vic-
tims. Because of this fact, and given the difficulty of neatly categorizing specific
mass murder events as shootings versus murder by other means, the study of mass
shootings benefits from an examination of mass murder.
As noted, mass shootings are a subset of mass murders; mass murder is also
a catastrophic but rare phenomenon (Burgess 2006; Investigative Assistance for
Violent Crimes Act of 2012, Pub. L. No. 112-265, 28 U.S.C. § 530C[b][1][M][i]).
Given its extremely low base rate, mass murder (and thus mass shootings) can-
not be predicted, especially by persons outside the perpetrator’s social circle
(Saleva et al. 2007). Little research exists that would serve to better inform men-
tal health professionals or law enforcement regarding the problems that lead in-
dividuals to commit mass murder.
For example, in a clinical study of 144 individuals who had threatened some
form of violence against others, 8 were found to have threatened mass homicide
(Warren et al. 2011). All 8 subjects said they had intended to kill as many people
as possible, and all cases involved targeting a specific group against whom the
would-be perpetrator held a grievance. Over the 12-month study period, none of
the 8 subjects carried out or attempted to carry out their plans. However, 2 of the
8 assaulted a person unrelated to the targeted group. Future research may enhance
awareness of the presence of “identification warning behaviors” (Meloy et al.
2011).
Factors common among individuals who commit mass murder include ex-
treme feelings of anger and revenge, the lack of an accomplice (when the per-
petrator is an adult), feelings of social alienation, and planning well in advance
of the offense. Many mass murderers do not plan to survive their own attacks and
intend to commit suicide or to be killed by police after committing their as-
saults. However, in a detailed case study of five mass murderers who did survive, a
number of common traits and historical factors were found. The subjects had all
been bullied or isolated during childhood and subsequently became loners who
felt despair over their social alienation. They demonstrated paranoid traits such
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

Mass Shootings and Mental Illness 85
as suspiciousness and grudge holding. Their worldview suggested a paranoid
mind-set; they believed others to be generally rejecting and uncaring. As a result,
they spent a great deal of time feeling resentful and ruminating on past humil-
iations. The ruminations subsequently evolved into fantasies of violent revenge
(Mullen 2004).
The Federal Bureau of Investigation (FBI) studied 160 cases of active shooter
incidents between 2000 and 2013 (Blair and Schweit 2014). An active shooter as
defined by the FBI and other federal agencies is “an individual actively engaged in
killing or attempting to kill people in a confined and populated area. Implicit in
this definition is that the subject’s criminal activities involve the use of firearms”
(Blair and Schweit 2014, p. 5). An average of 11.4 incidents of mass shooting oc-
curred annually, and the trend over the study period showed a steady rise in inci-
dents. The main findings of the FBI study included the following:
• Th e va st m ajo rit y of sho oti ngs (70% ) occ urre d in eit her a pl ace o f bu sin ess or
an educational environment.
• All but two of the shootings were carried out by a single individual.
• The shooter committed suicide in 64 (40%) of the cases.
• Most incidents (67%) ended before police even arrived and could engage the
perpetrator.
• Of the 160 incidents, 64 (40%) qualified as mass murder.
• Only 6 (3.8%) of the 160 cases involved a female perpetrator.
The U.S. Secret Service and the U.S. Department of Education conducted a
study focused on targeted school violence in the United States from 1974 to 2000
(Vossekuil et al. 2002). Therefore, this study involved shootings that had oc-
curred prior to the FBI study’s findings suggesting a trend of increased mass
shooting incidents from 2000 to 2013. Secret Service researchers analyzed 37 in-
cidents of targeted school violence (most of them involving guns) perpetrated
by 41 attackers during this time period. Key findings regarding school shooters
included the following:
• A majority of perpetrators (68%, n=28) acquired guns used from their own
or a relative’s home.
• Perpetrators had easy access to family-owned firearms.
• Perpetrators often “leaked” their intent to peers.
• Perpetrators often engaged in behavior prior to the incident that caused oth-
ers concern (e.g., weapon seeking, disturbing writings).
• Perpetrators had often considered or attempted suicide.
Chapter 5, “School Shootings and Mental Illness,” provides a more detailed dis-
cussion of school shootings.
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

86 GUN VIOLENCE AND MENTAL ILLNESS
From an etiological standpoint, the factors contributing to mass murder are
broad, and therefore analysis of any single incident should be approached using
a model that addresses individual biological, social, and psychological factors
(Aitken et al. 2008). Biological factors include possible brain pathology, as well
as psychiatric illnesses such as depression and psychosis. Psychological factors
include a negative or fragile self-image, paranoid dynamics, and retreat into vio-
lent and omnipotent revenge fantasies. Social factors include isolation, possible
ostracism by peers, and an absence of prosocial supports. In sum, the extant re-
search on mass murders suggests that these events are caused by a complex in-
teraction of emotional turmoil, psychopathology, traumatic life events, and other
precipitating factors unique to each case (Declercq and Audenaert 2011).
Careful study of individual cases of mass murder frequently reveals that the
offender felt compelled to leave some type of final message (Hempel et al. 1999;
Knoll 2010). These messages may be written, videotaped, or posted on the Inter-
net or social media networks (Aitken et al. 2008). The communications often
have great meaning to the perpetrators, who realize it will be the only “living” tes-
tament to their motivations and inner struggle (Knoll 2010). These messages are
rich sources of data that provide a more complete understanding of the perpetrator’s
motive, mental state, and psychological disturbances (Smith and Shuy 2002).
Available research has not produced a widely accepted typology of mass
murderers or mass shooters (Knoll 2012), and detailed examination of incidents
indicates that not all perpetrators are alike in their motivations and psychology.
Although no research has reliably established that most mass murderers and
mass shooters are psychotic or even suffering from a serious mental illness, in-
dividual case studies often reveal paranoid themes in these persons’ cognitions
(Knoll and Meloy 2014). The paranoia may not rise to the level of psychosis;
however, many are found to have been preoccupied with feelings of social per-
secution and fantasies of revenge against their perceived tormentors. Some ap-
pear to be driven by strong feelings of revenge born of social alienation or a
perceived injustice. For example, one 15-year-old who shot and killed his two
parents and two high school students and wounded another 25 students in 1998
in Springfield, Oregon (Frontline 2000) suffered intolerable anguish over feel-
ings of social rejection. His peers described him as morbid and preoccupied
with violence.
Others may in fact suffer from severe depression or, rarely, psychosis. For ex-
ample, in 2009, a 41-year-old naturalized Vietnamese immigrant killed 14 peo-
ple, wounded another 4, and then killed himself at the Binghamton, New York,
American Civic Association. The man’s father reported that in the 2 weeks lead-
ing up to the tragedy, his son had stopped eating dinner, stopped watching tele-
vision, and become increasingly isolative (Chen 2009). A few days after the shoot-
ing, a local television news station received a letter composed by the shooter and
postmarked the day of the shootings. Careful analysis of the letter revealed long-
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

Mass Shootings and Mental Illness 87
standing paranoid and persecutory delusions, as well as hallucinations (Knoll
2010). The shooter described his extreme resentment at being systematically
persecuted in a bizarre manner by “undercover cops,” whom he believed had de-
stroyed his chances of assimilating and working successfully in the United
States.
To date, the phenomenon of mass murder has also eluded classification in a
broadly accepted system. One proposed system is based on the concept of homi-
cide-suicide, derived from the work of Marzuk et al. (1992) and further adapted
by Knoll (2012). Homicide-suicide, an event in which an individual commits a
homicide and subsequently (usually within 24 hours) commits suicide (Bossarte
et al. 2006; Felthous and Hempel 1995), is a distinct category of homicide with
features that differ from other forms of killing. Homicide-suicide is also a rare
event, estimated to occur at a rate of 0.20–0.38 per 100,000 persons annually
(Bossarte et al. 2006; Coid 1983). The majority of homicide-suicides are carefully
planned by the perpetrator as a two-stage sequential act. Marzuk et al. (1992)
proposed classifying homicide-suicides by the relationship the perpetrator had to
the victim (e.g., spousal, familial), along with the perpetrator’s motive (e.g., jeal-
ousy, altruism, revenge) (Marzuk et al. 1992). Given that mass murder often ends
in the suicide of the perpetrator and has been described as “suicide with hostile
intent” (Preti 2008), a classification system similar to that used for homicide-
suicide would seem to make sense. An accepted classification system for mass
murder would be helpful in coordinating future research efforts. Table 4–1 gives
a proposed classification system for mass murder based on the homicide-suicide
classification system of Marzuk et al. (1992). In this proposed system, relation-
ship is defined as “relationship or link between victims and perpetrator” to em-
phasize the fact that some perpetrators may have no meaningful interpersonal
relationship with their victims but instead may have only a connection (link) via
some mutually shared activity such as work or school.
This relationship link-motive classification scheme allows for multiple
permutations that can be applied to best describe each individual case. Notably,
mental illness does not appear consistently as a factor except in two of the six
classification groups. For example, in this system, the School-Resentful type of
mass murderer includes offenders who target schoolmates and have the motive
of hostile revenge. Depression and/or suicidal threats are likely to be present
prior to the offense, but not necessarily. These individuals are often described as
bullied, disaffected, or socially alienated students who are motivated by feelings
of rejection or humiliation by peers. The perpetrator often communicates intent
to third-party peers (Knoll 2012; Vossekuil et al. 2002). Examples of murderers
who fit this description include the shooters at Virginia Tech and Columbine,
Colorado (Cullen 2010).
The Workplace-Resentful type describes the aggrieved or disgruntled em-
ployee or ex-employee who is upset with a supervisor, coworker(s), or some
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

88 GUN VIOLENCE AND MENTAL ILLNESS
TABLE 4–1. Proposed classification system for incidents of mass murder
Type Victim Relationship Motive Offense location
Paranoid
cognitions SMI
School-Resentful Peers, teachers Yes Resentment/revenge Educational environment + +/–
Workplace-Resentful Coworkers,
supervisors
Yes Resentment/revenge Place of business + +/–
Indiscriminate-Resentful Arbitrary No Resentment/anger Variable, place of easy
access to many victims
++/–
Specific Community–
Resentful
Identifiable group,
culture, or political
movement
Variable Resentment/revenge Variable according to
location of targeted group
++/–
Pseudocommunity-Psychotic Misperceived
persecutors
Variable Paranoid delusions Variable according to
persecutory delusion
++
Familial-Depressed Family, spouse, or
ex-spouse
Yes Severe depression
Possible psychosis
Revenge
Family domicile + +
Note. Classification scheme: relationship (relationship or link between victims and perpetrator)+motive (primary rationale driving the perpetrator). SMI=serious
mental illness, defined as psychosis or delusional disorder meeting DSM-5 diagnostic criteria (American Psychiatric Association 2013).
Source. Adapted from Knoll 2012 and Marzuk et al. 1992.
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

Mass Shootings and Mental Illness 89
aspect of the work environment and who commits murder in the workplace. These
individuals typically externalize blame for their problem onto others and feel
they have been wronged. They are very likely to have depression, as well as par-
anoid and/or narcissistic traits. Persecutory delusions may sometimes be seen;
howe ver, me ntal i llnes s is no t nece ssa rily p resent. An exa mple of t his cate gor y is
the Atlanta day trader who shot and killed 9 people and injured 13 more in 1999.
He entered two adjacent Atlanta day-trading firms, stating, “I hope this doesn’t
ruin your trading day” before carrying out the shootings. Shortly afterward, he shot
himself. This individual was motivated by depression and anger, as well as seri-
ous financial and marital troubles. He had developed a highly resentful, hopeless
attitude about his life and career. His suicide note stated, “I don’t plan to live very
much longer, just long enough to kill as many of the p eople that greedily sought
my destruction” (Barton 1999; Cohen 1999).
The Indiscriminate-Resentful type describes the generally rageful, depressed,
and often paranoid individual who vents anger arbitrarily in some public place.
The victim group may be chosen randomly or on the basis of convenience or ease
of access to large numbers of people. An example of t his category is the man who
shot and killed 22 and injured 19 others at a San Diego, California, McDonald’s
restaurant in 1984 (Mitchell 2002). This angry but nonpsychotic man told his
wife immediately prior to the offense that “society had their chance” and that he
was leaving to go “hunting humans.” No evidence indicated that he felt particu-
larly aggrieved by that specific McDonald’s restaurant or its employees. Rather,
the evidence indicated that he had chosen the location due to his familiarity with
his target and his knowledge that large numbers of potential victims were likely
to be present.
In a seminal paper on mass, serial, and sensational homicides, Park Dietz
(1986) described a type of mass murderer he termed the “pseudocommando,” who
plans out the offense ritualistically and comes prepared with a powerful arsenal
of weapons. The proposed classification system includes two types of pseudo-
commando-style mass murderers: the Specific Community–Resentful type and
the Pseudocommunity-Psychotic type. Both categories include individuals who
have paranoid character traits and are driven by strong feelings of anger and re-
sentment.
The Specific Community–Resentful type may include disgruntled clients or
others harboring deep resentment toward an identifiable group, culture, or polit-
ical movement. In contrast, the Pseudocommunity-Psychotic type includes only
those experiencing paranoid or persecutory delusions flowing from a psychotic
disorder. In terms of the relationship to the victims, the pseudocommando-
ps ycho tic mass mur derer foc uses o n a g roup that he d elusi onall y be lie ves is per-
secuting him. Dietz noted that the pseudocommando may focus his resentment
on a specific community based in reality or on a “pseudocommunity” that he
defines on the basis of psychosis or strong paranoid cognitions.
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

90 GUN VIOLENCE AND MENTAL ILLNESS
Finally, the Familial-Depressed type involves a member of a family unit who
is suffering from severe depression with possible psychotic features. Motives
may flow from cognitions distorted by depression and hopelessness, psychosis,
and/or resentment toward an estranged spouse. A typical scenario involves a
depressed father who kills his entire family, viewing the act as a delivery of his
family from what he perceives to be continued hardship or stressors (Selkin
1976).
MASS SHOOTINGS AND MENTAL ILLNESS:
IS THERE A CONNECTION?
The publicity regarding mass shootings unfortunately overshadows another
public health tragedy that affects exponentially more people: the daily toll of
morbidity and mortality due to the more common types of gun violence, includ-
ing suicide. Rarely, if ever, do these events receive the same media attention as
mass shootings (Pinals et al. 2014). As discussed in Chapter 2, “Firearms and Sui-
cide in the United States,” evidence overwhelmingly demonstrates that suicide,
not homicide, is the most significant public health concern in terms of guns and
mental illness. Indeed, the small amount of research on firearm removal laws
suggests that removal by police “was rarely a result of psychosis; instead, risk of
suicide was the leading reason” (Parker 2010, p. 241).
Even if one assumes a direct association between violence against others and
serious mental illness, the focus must be narrowed to the population of indi-
viduals with serious mental illness associated with less than 3% of all violence
(Fazel and Grann 2006). Furthermore, current research suggests that in general
there is a minimal relationship between psychiatric disorders and violence in the
absence of substance abuse (Martone et al. 2013). Thus, the assumption that all
persons with mental illness are a “high-risk” population relative to violence gen-
erally and gun violence in particular lacks supportive evidence. The likelihood
of error and oversimplification is substantial when mental illness is considered
on “the aggregate level” such that a “vast and diverse population of persons di-
agnosed with psychiatric conditions” is considered to uniformly represent people
who are at risk of committing gun violence against others (Metzl and Macleish
2015, p. 241).
Some research has identified a small but higher fraction of homicides (not
specific to those involving firearms) committed by individuals with schizophre-
nia than by those in the general population (Bennett et al. 2011; Schanda et al.
2004). Despite this small but elevated risk, the rate of stranger homicides com-
mitted by individuals with schizophrenia or chronic psychosis is extremely low. On
the basis of a meta-analysis from 1999, one stranger homicide is perpetrated by
someone with a psychotic illness per year in a population of 14.3 million (Niels-
sen et al. 2011). Assuming a U.S. population of 320 million, approximately 23 peo-
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

Mass Shootings and Mental Illness 91
ple a year on average are killed by an individual with a psychotic illness. In con-
trast, an average of about 330 people in the United States are struck by lightning
per year (Jensenius 2014). A person is about 15 times more likely to be struck by
lightning in a given year than to be killed by a stranger with a diagnosis of schizo-
phrenia or chronic psychosis.
Few perpetrators of mass shootings have had verified histories of being in
psychiatric treatment for serious mental illness. Rather, detailed case analyses
reveal that individuals who commit mass shootings often feel aggrieved, are ex-
tremely angry, and have nurtured fantasies of violent revenge (Knoll 2010). Such
individuals function (perhaps marginally) in society and do not typically seek out
mental health treatment. Thus, in most cases, it cannot fairly be said that a per-
petrator “fell through the cracks” of the mental health system. Rather, these in-
dividuals typically plan their actions well outside the awareness of mental health
professionals.
SALIENT YET UNDEREXPLORED SOCIOCULTURAL FACTORS
IN MASS SHOOTINGS
The majority of attention following mass shootings focuses on the role of mental
illness, and sociocultural factors have received comparatively little examination.
Gun violence “in all its forms has a social context,” which is not meaningfully
captured by psychiatric diagnoses in isolation (Metzl and Macleish 2015, p. 247).
Mass shootings by disgruntled individuals have occurred in Western civiliza-
tion since the invention of the gun. Alienation and social rejection are social
phenomena that undoubtedly existed even before recorded history. Neverthe-
less, mass shootings over the past two to three decades have led to speculation
about whether these differ from mass shootings of the past or whether they rep-
resent the same phenomenon in a more modern age. Another salient concern
is whether the powerful social influence of today’s media and Internet technol-
ogy plays a significant role.
As noted above (see “Mass Shootings: What Is Known”), the FBI study finding
that the incidence of mass shootings has increased over the past decade hints at
other, possibly more relevant factors associated with these events relative to
mental illness or psychiatric diagnosis. Since the 1990s, mass murders, and es-
pecially mass shootings, have arguably taken on a different quality, influenced
by a cultural shift, social media, and expansive news coverage of the tragedies.
Mullen (2004) described the results of his detailed forensic evaluations of five
pseudocommando mass shooters who were captured before they were killed or
could commit suicide. Most perpetrators acknowledged being influenced by
previous mass killers who received significant media exposure. This led Mullen
to propose the concept of a Western cultural “script” as one of several factors
that contribute to the propagation of these tragic events.
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

92 GUN VIOLENCE AND MENTAL ILLNESS
Certain psychosocial characteristics are common among perp etrators of mass
shootings. These include problems with self-esteem, a persecutory/paranoid
outlook, narcissism, depression, suicidality, and a perception of being socially
rejected (Knoll 2012; Modzeleski et al. 2008; Mullen 2004; O’Toole 2000). In a
review of school-associated homicides in K–12 settings, Flannery et al. (2013)
noted that “[a] need remains for researchers and commentators to examine other
factors beyond the individual that may explain school shootings, including cul-
ture, the social ecology of the school or other community factors” (Flannery et
al. 2013, p. 6). They cited studies (Brown et al. 2009; Flannery et al. 2001) sug-
gesting differences between urban and suburban school shootings, and pro-
posed that some acts are related to the perpetrator’s perception of threats to his
social identity. Suburban and rural shootings may be characterized by social
alienation, whereas urban incidents are typically associated with interpersonal
violence, often in the context of different kinds of relationships (see Chapter 3,
“Gun Violence, Urban Youth, and Mental Illness”). Social marginalization and
familial dysfunction are other common findings among mass shooters (New-
man et al. 2005).
The call to investigate cultural and community factors seems particularly
meaningful when attention is paid to the messages perpetrators leave behind.
For example, one mass shooter from Montreal, Quebec, in 2006 wrote, “It’s so-
ciety’s fault.. .. Society disgusts me” (Langan 2006). The Sandy Hook Elementary
School (Newtown, Connecticut) shooter posted online in late 2011, “[You know
what I hate]...Culture. I’ve been pissed out of my mind all night thinking about
it” (Sandy Hook Lighthouse 2014). The Isla Vista, California, shooter posted
a manuscript online in 2014 stating, “Humanity is a cruel and brutal species”
(Rodger 2014). Further investigation of sociocultural factors of mass shootings,
particularly in Western society, necessitates a consideration of the issues of nar-
cissism and media responsibility.
NARCISSISM AND MASS SHOOTINGS
Narcissism may be considered the classic American pathology (Twenge et al.
2008), but concern is growing that it may be proliferating “virally” and gaining
momentum (Twenge and Campbell 2009). Is the changing character of mass
shootings over the past few decades due, in part, to our society’s increasingly
narcissistic values (Twenge et al. 2012)? Narcissism has been demonstrated in
the motivations and statements made by certain mass shooters since the 1990s.
In 2007, a man who shot nine people in an Omaha, Nebraska, mall before kill-
ing himself left a suicide note that stated, “Just think tho [sic] I’m gonna be fa-
mous” (Kluger 2007; Nichols 2007). A similar message was communicated by
the Columbine offenders, who stated on a preshooting video, “Isn’t it fun to get
the respect we’re going to deserve?” (Twenge and Campbell 2003, p. 261).
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

Mass Shootings and Mental Illness 93
Twenge and Campbell (2009) noted that crime has dropped overall since the
1990s due to a variety of factors, but crimes related to narcissism (or a wounded
ego) have not had a corresponding drop and are directly relevant to mass shoot-
ings. These authors further noted that “narcissism and social rejection were two
risk factors that worked together to cause aggressive behavior” (p. 199), and these
factors have certainly been apparent in the histories of mass shooters. They con-
cluded, “Given the upswing in the narcissistic values of American culture since
the ’ 90s, it may b e no coincide nce that mass shoo ting s became a nat iona l pla gue
around the same time” (p. 200).
Similarly, Pinker (2011) has laid out a comprehensive overview of how vi-
olence among Homo sapiens has greatly declined over the centuries due to a
“civilizing process,” but speculates that humans might have reached a point of
limited returns. He indicates that further gains, which may be harder to attain,
arguably also lie in the realm of attenuating the problem of narcissism.
Extensive media attention in the 1990s may have propagated the Western
“script” described by Mullen (2004), resulting in a perverse glamorization of the
act of mass killing, particularly in the eyes of subsequent perpetrators. The study of
individual cases of mass shootings that have occurred since the 1990s suggests that
perpetrators often felt socially rejected and perceived society as continually de-
nouncing them as unnecessary, ineffectual, and pathetic. Instead of bearing the
burden of the humiliation, they plan a surprise attack to prove their hidden “value.”
Narcissism is strengthened and rigidified by obsessive ruminations along
the lines of “I am right and I’ve been treated badly or wronged (by other people or
by life).” It could be said that the mass sho oter’s persecutory and narcissistic mind-
set seeks a form of reverse specialness. By becoming a lone protestor against an
“unjust” reality, the mass shooter creates and assumes a powerful victim role in
which he can “win”—even by losing. This interest in the narcissistic antihero has
conspicuously permeated Western fiction and popular culture, in which follow-
ers thrill to the exploits of characters who possess the “dark triad” of personality:
narcissism, psychopathy, and Machiavellianism (Jonason et al. 2012). Western
society in particular has had a long-standing fascination with the antihero, the
outlaw, the Bonnies and Clydes and John Dillingers of American history (Kun-
hardt and Kunhardt 1995; Spillane 1999). Their short, violent lives became the
stuff of romanticized, tragic legend.
Western culture has also come to include a vast and powerfully influential
value system devoted to celebrity and fame. In place of what should be profound
shame, an aura of undeserved notoriety and infamy is often accorded to certain
individuals who commit horrible crimes (Brin 2012). The very public, dramatic,
and at times theatrical nature of mass murder seems to speak to a “need for rec-
ognition from an audience” (Neuman 2012, p. 2). The staged and exposed act of
revenge has the function of establishing a connection with spectators who will
not soon forget what they have seen.
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

94 GUN VIOLENCE AND MENTAL ILLNESS
It might be theorized that the Internet and social media have amplified the
high value placed on celebrity and the Western cultural script of the tragic anti-
hero. The use of video-sharing Web sites and other Internet platforms perpetu-
ates the alienated loner’s conflict: his wish for social connection versus his deep-
seated mistrust of others. This can create an isolating virtual socialization that is
sustained well into young adulthood, leaving the individual without real expe-
ri enc e in d eve lop ing hea lthy soc ial a tta chm ent s, a nd r esu lti ng u lti mat ely in f eel -
ings of being unwanted. The final written communication of the Isla Vista
shooter reflects precisely such a pattern of alienation and malignant envy, cul-
minating in a violent bid for fame and validation: “Humanity has rejected me....
Exacting my Retribution is my way of proving my true worth to the world” (Rod-
ger 2014).
MEDIA COVERAGE: RESPONSIBLE REPORTING AND STIGMA
After the Sandy Hook tragedy in 2012, a senator announced that he supported mea-
sures to keep guns “out of the hands of criminals and the mentally ill” (Strauss
2012). Shortly thereafter, a National Rifle Association official stated in a press
conference that “our society is populated by an unknown number of genuine
monsters. People that are so deranged, so evil, so possessed by voices and driven
by d emons, that no sane pe rson can e ven p ossibly comp rehend them. . . .How ca n
we possibly even guess how many, given our nation’s refusal to create an active
national database of the mentally ill?” (The Washington Post 2012). Such state-
ments, widely disseminated by the media, reinforce the existing societal presump-
tive association between “criminals,” “evil,” and “the mentally ill.” In fact, such
misguided associations need no further reinforcement. The lay public requires
little persuasion to associate mental illness with criminality and evil (Coulter
2013).
Significant research data indicate that erroneous and negative attitudes to-
ward persons with mental illness are widespread in society (Bizer et al. 2012).
The term stigma is synonymous with shame, disgrace, and humiliation. To stigma-
tize means to brand, slur, or defame. Fear, anxiety, and the need to find quick and
clear-cut solutions lead to common but mistaken beliefs that reinforce the stig-
matization of individuals with mental illness. These myths include beliefs that
people with mental illness (Link et al. 1999) are more dangerous than people
without mental illness, are personally to blame for their illness, and have no
“se lf-c ont rol .”
Approximately 50 years after deinstitutionalization of individuals with mental
illness, the misconception that these persons are “ticking time bombs, ready to
explode into violence” remains a deeply ingrained societal belief (Appelbaum
2004). Research by Link et al. (1999) demonstrated strong stereotypes of these
individuals’ dangerousness and the desire for social distance from those with men-
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

Mass Shootings and Mental Illness 95
tal illness. Comparing the research from 1950 with that of 1996 further indicates
that perceptions of persons with mental illness as violent or frightening have
substantially increased rather than decreased. In short, persons with serious
mental illness are more feared today than they were half a century ago (Phelan et
al. 2000). One of the most problematic results of laws that perpetuate the myth
tha t m ent al il ln es s i s lin ke d t o g un vi ole nc e i s t he rei nf or cem en t o f su ch ne gativ e
stereotypes. Such reinforcement adds to the considerable stigma associated with
mental illness, while having no appreciable effects on the incidence of mass kill-
ings that often drive the policy interventions.
Early news media coverage after a mass shooting may refer to the shooter as
“mentally unstable” or “mentally ill,” often prior to gathering any definitive infor-
mation. News debate shows often feature speakers who call for measures such as
creating a database of individuals with mental illness in an effort to prevent fur-
ther tragedies. Such dialogue is unhelpful and further strengthens erroneous
public views about mental illness and gun violence. Media coverage following
collective traumas has been observed to have public health effects, particularly
in terms of stress-related symptoms (Holman et al. 2014). With increasing re-
liance on social media as a source of news, media errors may easily exacerbate
public stress, as well as exacerbate the problem of sensationalizing tragedies
(Berkowitz and Liu 2014).
Thus, interventions designed to improve media responsibility should dissuade
this and similar dialogue in the aftermath of a mass shooting. Efforts to develop
a universal reporting code that would appropriately cover the tragedy and re-
duce the impact of the “copycat” effect have been recommended; these generally
include avoiding emphasis on perpetrators and neither glorifying nor demon-
izing them (Etzersdorfer and Sonneck 1998). Media should consider avoiding
much emphasis on the perpetrator while emphasizing victim and community
recovery efforts. Future research should focus more distinctly on which ele-
ments of media coverage are problematic and which are more effective in pro-
moting public health goals (Schildkraut and Muschert 2013).
INTERVENTIONS TO PREVENT MASS SHOOTINGS
GUN LAWS FOCUSING ON MENTAL ILLNESS
Equating mental illness and gun violence toward others in an effort to solve
the overall problem of gun violence in the United States is an example of what
the Greek philosopher Epictetus described as grasping a problem “by the wrong
handle” (Gutheil et al. 2005; Pies 2008). In the wake of a frightening tragedy,
reactive attempts to reduce gun violence by focusing on people with mental
illness represent an intervention with no supportive evidence of practical
efficacy.
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

96 GUN VIOLENCE AND MENTAL ILLNESS
From 2007 to 2013, as a result of the National Instant Criminal Background
Check System (NICS) Improvement Act of 2008, mental health record submis-
sions to NICS increased tenfold (Federal Bureau of Investigation 2013, 2014).
Less than 1% of all firearm purchase denials were based on these records (Swan-
son et al. 2015). However, during this same period, the FBI’s study of active shoot-
ers reflected an increasing trend of mass shooting incidents (Blair and Schweit
2014). The NICS background check system requires, for reporting regarding
mental health, that the individual have a history of prior civil commitment, a le-
gal adjudication of not guilty by reason of insanity, or an adjudication of not
competent to stand trial. Thus, for a background check to deny firearm purchase
to a potential mass shooter, that individual would have to 1) have a history of
prior civil commitment (and that history would have had to have been reported
to NICS) and 2) attempt to purchase a gun legally. The existing body of research
on mass shooters suggests that a history of civil commitment or legal adjudica-
tion of criminal insanity or incompetence to stand trial is practically unheard of
among perpetrators of mass homicide and mass homicide-suicide.
Recalling the very low percentage of violent acts that are attributable to se-
rious mental illness, and considering that most of these acts do not involve guns,
it becomes difficult to avoid the conclusion that the contribution to public safety
of laws directed toward individuals with mental illness in preventing gun vio-
lence is likely to be small (Appelbaum and Swanson 2010). In addition, these spe-
cial laws require resources and funding when cost-effective use of resources is a
pressing matter. It would seem imperative to “question whether a comprehen-
sive registry [of individuals with mental illness] would have prevented any of
the mass killings in recent years, and whether the expenditures of the more than
one hundred million dollars needed to create and maintain the registries for
persons with mental health histories could be better spent on broader public-
safety targeted interventions that might yield greater overall benefits to society”
(Pinals et al. 2014, p. 2).
EFFORTS TO IDENTIFY EFFECTIVE INTERVENTIONS
Mass shootings are multidetermined, extremely rare events with no simple pre-
ventive solution. The fact that they occur “too infrequently to allow for statis-
tical modeling” suggests that a focus on mass shootings will serve as a question-
able “jumping-off” point for “effective public health interventions” (Metzl and
Macleish 2015, p. 426). Although research suggests that in recent years the in-
cidence of these events may be increasing (see earlier section “Mass Shootings:
What Is Known”), mass shootings are still relatively infrequent, making these
tragedies exceptionally hard to anticipate and avert (Blair and Schweit 2014;
Saleva et al. 2007). Given the extremely low base rate of mass murder in general
and of mass shootings in particular, psychiatric efforts will be best spent in di-
rections other than prediction (Dressing and Meyer-Lindenberg 2010).
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

Mass Shootings and Mental Illness 97
Prevention efforts must rely on multiple approaches used in conjunction to
provide the widest possible safety net. For example, third parties, particularly
family members, have important roles because they are the most likely to have
preoffense knowledge or significant concerns (Associated Press 2007). In addi-
tion, potential mass murderers often leak their intent to third parties who may not
report violent threats or plans to authorities for various reasons (Katsavdakis et al.
2011; Kluger 2007), including not recognizing the seriousness of the potential
threat.
Nevertheless, as Aitken et al. (2008) note, “prevention may only be possible
when somebody warns that such behavior may occur....Acquaintances often
acknowledge concerns prior to the incident” (p. 265). Messages or leaked intent
may be communicated verbally, or in writing via Internet pages, or through so-
cial media outlets such as YouTube. Family members or social contacts may be
the only people in a position to take steps to have the potential offender evalu-
ated and treated (Orange 2011). Therefore, family members of individuals who
may present with increased risk of gun violence, with or without mental illness,
should be provided with information about existing help and resources. They
should be provided with support for notifying authorities and understand that
doing so is a potentially heroic and compassionate act that may save the lives of
others as well as their loved one’s.
The FBI study of active shooters concluded that training and exercises for both
police and citizens were indicated, especially given the brief period over which the
shootings unfold (Blair and Schweit 2014). However, the FBI study placed pri-
mary emphasis on prevention efforts from a community standpoint. Future re-
search should consider mass shootings that were prevented and/or aborted,
with an eye toward identifying crucial preventive factors. Specialized threat assess-
ment teams in Australia and the United Kingdom have been helpful in terms of
enhancing prevention of low-frequency, high-intensity events (Meloy and
Hoffmann 2014). Similar multidisciplinary teams in the United States should be
explored, w ith a focus on the two areas of greatest concern noted in the FBI study:
places of education and workplace violence.
For general mental health professionals, careful clinical risk assessment and
management may be stressed as a part of overall competent psychiatric patient
care (Mills et al. 2011; Swanson 2008). Future research will undoubtedly enhance
awareness of “warning behaviors” for targeted violence, and mental health clini-
ci an s w il l b est se r ve p at ie nts at ri sk b y c raf ti ng a r is k m ana ge men t p la n at cl in ica ll y
relevant or critical times (Meloy et al. 2011). Special attention should be given
to “availability of means, planning, preparation, and the acknowledged commit-
ment to put the words into action irrespective of consequences” (Warren et al.
2011, p. 151). Risk assessments of individuals with strong revenge fantasies will
need to consider the intensity and quality of these fantasies, vulnerability to ego
threats, and relevant biopsychosocial variables (Baumeister et al. 1996).
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

98 GUN VIOLENCE AND MENTAL ILLNESS
Public education regarding mental illness and effective interventions can
serve to lessen fears of those with serious mental illness and decrease the stigma
attached to serious mental illness. For many decades, sexual health education
has been taught to teens and adolescents. However, a similar focus on mental
health education is rare in children’s early education. Well-informed and com-
passionate education on mental health and mental wellness may not only re-
duce future stigma but also serve as a beneficial public health intervention. Such
education could become increasingly sophisticated as children progress through
school. In particular, this education may serve as an early preventive effort, while
encouraging more open discussion in schools about important mental health
issues.
CONCLUSION
Mass shootings by people with serious mental illness remain exceedingly rare
events and represent a fraction of a percent of all yearly gun-related homicides.
In contrast, firearm deaths by suicide account for the majority of yearly gun-
related deaths. Although gun restriction laws that focus broadly on mental ill-
ness are an understandable initial reaction, they will be extremely low yield
and wasteful of scant resources. Furthermore, such laws perpetuate the myth
that mental illness leads to violence and gives the public the incorrect message
that me ntal i llnes s is significantl y asso ciated w ith gu n viol ence d irected toward
others.
The problem of mass shootings and the motives of the shooters in present-
day society stand apart from mental illness generally. The recent phenomenon of
mass shootings in the United States is likely a result of a combination of factors,
in cludi ng s oci ocu ltu ral ones tha t must be b ett er und ers too d if the se t raged ies are
to be prevented. Mental health clinicians will best serve patients at risk of harm
to themselves and/or others by crafting a risk management plan at clinically rel-
evant or critical times. As opposed to prediction, structured clinical risk assess-
ment and management may be stressed as part of an overall competent psychi-
atric patient care effort (Knoll 2009; Swanson 2008; Webster et al. 2013).
Whether or not individuals who perpetrate mass shootings suffer from a di-
agnosable serious mental illness, they do have an ill-defined trouble of the mind
for which the mental health field has no immediate, quick-acting “treatment.”
That said, if such individuals were motivated to overcome long-standing, per-
vasive feelings of anger, persecution, revenge, and egotism rather than act on
them, they would presumably be more likely to improve their circumstances in
nonviolent ways. Psychiatry may be able to assist individuals who are determined
and willing to engage in treatment, form healthy social connections, and pursue
other prosocial interventions. For these individuals, more resources need to be
made available, as discussed elsewhere in this volume.
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

Mass Shootings and Mental Illness 99
Unfortunately, some disturbed individuals are likely to remain inaccessible
to whatever interventions mental health professionals have to offer. This situa-
tion accounts, at least in part, for the fact that measures such as screening for
prior psychiatric treatment (often in the distant past) among individuals who
want to legally purchase firearms do not represent meaningful interventions
(Brady Handgun Violence Prevention Act of 1993, Pub. L. No. 103-159, 18
U.S.C. § 922 [s1–s6]; Norris et al. 2006; Simpson 2007). Experience and research
have demonstrated that more promising, higher-yield interventions include
both 1) third-party reporting of warning behaviors or leaked intent and 2) social
and media responsibility (Meloy and O’Toole 2011; Meloy et al. 2011; O’Toole
2014).
On a fundamental level, the behavior and motives of mass shooters must be
distinguished from psychiatric diagnoses. The belief that these categories over-
lap or have a direct causal association is not supported by available evidence.
More importantly, interventions to decrease the morbidity and mortality of gun
violence based on such overgeneralized views are not likely to be successful and
may cause more harm than good.
Suggested Interventions
Policies and laws should focus on those individuals whose be-
haviors identify them as having increased risk for committing
gun violence, rather than on broad categories such as mental ill-
ness or psychiatric diagnoses.
Public health educational campaigns should emphasize the
need for third-party reporting of intent or concerning warning
behaviors to law enforcement.
Institutions and communities should develop specialized foren-
sic threat assessment teams to evaluate third-party reports of
potential dangerousness.
Resources should be increased to provide enhanced education,
beginning in elementary school, with a focus on constructive cop-
ing skills for anger and conflict resolution, mental health, and
mental wellness education.
REFERENCES
Aitken L, Oosthuizen P, Emsley R, et al: Mass murders: implications for mental health
professionals. Int J Psychiatry Med 38(3):261–269, 2008 19069571
American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disor-
ders, 5th Edition. Arlington, VA, American Psychiatric Association, 2013
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

100 GUN VIOLENCE AND MENTAL ILLNESS
Appelbaum PS: Law and psychiatry: “One madman keeping loaded guns”: misconcep-
tions of mental illness and their legal consequences. Psychiatr Serv 55(10):1105–
1106, 2004 15494320
Appelbaum PS, Swanson JW: Law and psychiatry: gun laws and mental illness: how sen-
sible are the current restrictions? Psychiatr Serv 61(7):652–654, 2010 20591996
Associated Press: Mass public shootings on the rise, but why? Massacre at Virginia Tech
on NBC News, April 21, 2007. Available at: http://www.msnbc.msn.com/id/
18249724/. Accessed January 8, 2015.
Barton MO: Shootings in Atlanta: The Notes. New York Times, July 31, 1999. Available
at: http://www.nytimes.com/1999/07/31/us/shootings-in-atlanta-the-notes-there-
is-no-reason-for-me-to-lie-now.html. Accessed January 8, 2015.
Baumeister RF, Smart L, Boden JM: Relation of threatened egotism to violence and ag-
gression: the dark side of high self-esteem. Psychol Rev 103(1):5–33, 1996 8650299
Bennett DJ, Ogloff JR, Mullen PE, et al: Schizophrenia disorders, substance abuse and
prior offending in a sequential series of 435 homicides. Acta Psychiatr Scand
124(3):226–233, 2011 21644942
Berkowitz D, Liu ZM: Media errors and the “nutty professor”: riding the journalistic
boundaries of the Sandy Hook shootings. Journalism, October 9, 2014 doi:10.1177/
1464884914552266
Bizer G, Hart J, Jekogian A: Belief in a just world and social dominance orientation: ev-
idence for a mediational pathway predicting negative attitudes and discrimination
against individuals with mental illness. Pers Individ Dif 52(3):428–432, 2012
Blair J, Schweit K: A Study of Active Shooter Incidents in the United States Between 2000
and 2013. Washington, DC, Federal Bureau of Investigation, 2014
Bossarte RM, Simon TR, Barker L: Characteristics of homicide followed by suicide inci-
dents in multiple states, 2003–04. Inj Prev 12 (suppl 2):ii33–ii38, 2006 17170169
Brin D: Names of infamy: deny killers the notoriety they seek. Contrary Brin, July 21,
2012. Available at: http://davidbrin.blogspot.com/2012/07/names-of-infamy-deny-
killers-notoreity.html. Accessed January 8, 2015.
Brown RP, Osterman LL, Barnes CD: School violence and the culture of honor. Psychol
Sci 20(11):1400–1405, 2009 19843260
Burgess AW: Mass, spree and serial homicide, in Crime Classification Manual, 2nd Edi-
tion. Edited by Douglas J, Burgess AW, Burgess AG, et al. San Francisco, CA, Jossey-
Bass, 2006
Chen P: Jiverly Wong’s father: what prompted mass killing in Binghamton remains a mys-
tery. The Post Standard, April 13, 2009. Available at: http://www.syracuse.com/news/
index.ssf/2009/04/jiverly_wongs_father_our_son_w.html. Accessed August 4, 2015.
Cohen A: A portrait of the killer. Time, August 9, 1999. Available at: http://www.time.com/
time/magazine/article/0,9171,991676,00.html?promoid=googlep. Accessed Janu-
ary 8, 2015.
Coid J: The epidemiology of abnormal homicide and murder followed by suicide. Psy-
chol Med 13(4):855–860, 1983 6607479
Coulter A: Guns don’t kill people, the mentally ill do. MRC NewsBusters, January 16,
2013. Available at: http://www.anncoulter.com/columns/2013-01-16.html. Ac-
cessed August 4, 2015.
Cullen D: Columbine. Lebanon, IN, Twelve, 2010
Declercq F, Audenaert K: Predatory violence aiming at relief in a case of mass murder:
Meloy’s criteria for applied forensic practice. Behav Sci Law 29(4):578–591, 2011
21748789
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

Mass Shootings and Mental Illness 101
Dietz PE: Mass, serial and sensational homicides. Bull NY Acad Med 62(5):477–491,
1986 3461857
Dressing H, Meyer-Lindenberg A: Risk assessment of threatened amok: new responsi-
bilities for psychiatry? [in German] Nervenarzt 81(5):594–601, 2010 20221743
Duwe G: A circle of distortion: the social construction of mass murder in the United
States. West Crim Rev 6(1):59–78, 2005
Etzersdorfer E, Sonneck G: Preventing suicide by influencing the mass media reporting:
the Viennese experience, 1980–1996. Arch Suicide Res 4(1):67–74, 1998
Fazel S, Grann M: The population impact of severe mental illness on violent crime. Am
J Psychiatry 163(8):1397–1403, 2006 16877653
Federal Bureau of Investigation: National Instant Criminal Background Check System,
Operations Report: 2012. Washington, DC, Federal Bureau of Investigation, 2013.
Available at: www.fbi.gov/about-us/cjis/nics/reports/2012-operations-report. Ac-
cessed January 8, 2015.
Federal Bureau of Investigation: National Instant Criminal Background Check System,
Operations Report: 2013. Washington, DC, Federal Bureau of Investigation, 2014.
Available at: www.fbi.gov/about-us/cjis/nics/reports/2013-operations-report. Ac-
cessed January 8, 2015.
Felthous AR, Hempel A: Combined homicide-suicides: a review. J Forensic Sci 40(5):846–
857, 1995 7595329
Flannery DJ, Singer MI, Wester K: Violence exposure, psychological trauma, and suicide
risk in a community sample of dangerously violent adolescents. J Am Acad Child
Adolesc Psychiatry 40(4):435–442, 2001 11314569
Flannery DJ, Modzeleski W, Kretschmar JM: Violence and school shootings. Curr Psy-
chiatry Rep 15(1):331–337, 2013 23254623
Frontline: The killer at Thurston High. January 18, 2000. Available at: http://www.pbs.org/
wgbh/pages/frontline/shows/kinkel/kip/cron.html. Accessed January 27, 2015.
Gutheil TG, Simon RI, Hilliard JT: “The wrong handle”: flawed fixes of medicolegal
problems in psychiatry and the law. J Am Acad Psychiatry Law 33(4):432–436,
2005 16394218
Hempel AG, Meloy JR, Richards TC: Offender and offense characteristics of a nonrandom
sample of mass murderers. J Am Acad Psychiatry Law 27(2):213–225, 1999 10400430
Holman EA, Garfin DR, Silver RC: Media’s role in broadcasting acute stress following
the Boston Marathon bombings. Proc Natl Acad Sci US A 111(1):93–98, 2014
24324161
Jensenius JS Jr: National Weather Service Lightning Safety: Understanding Lightning.
Silver Spring, MD, National Oceanic and Atmospheric Administration, 2014.
Available at: http://www.lightningsafety.noaa.gov/science/scienceintro.htm. Ac-
cessed January 8, 2015.
Jonason P, Webster G, Schmitt D, et al: The antihero in popular culture: life history the-
ory and the dark triad personality traits. Rev Gen Psychol 16(2):192–199, 2012
Katsavdakis KA, Meloy JR, White SG: A female mass murder. J Forensic Sci 56(3):813–
818, 2011 21291471
Kluger J: Inside a mass murderer’s mind. Time, April 19, 2007. Available at: http://
www.time.com/time/magazine/article/0,9171,1612694,00.html. Accessed January
8, 2015.
Knoll JL IV: Violence risk assessment for mental health professionals, in Wiley Encyclo-
pedia of Forensic Science. Edited by Jamieson A, Moenssens A. Chichester, UK,
Wiley, 2009, pp 2597–2602
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

102 GUN VIOLENCE AND MENTAL ILLNESS
Knoll JL IV: The “pseudocommando” mass murderer, part II: the language of revenge.
J Am Acad Psychiatry Law 38(2):263–272, 2010 20542949
Knoll JL IV: Mass murder: causes, classification, and prevention. Psychiatr Clin North
Am 35(4):757–780, 2012 23107562
Knoll J IV, Meloy JR: Mass murder and the violent paranoid spectrum. Psychiatr Ann
44(5):236–243, 2014
Kunhardt P, Kunhardt P III: Violence: An American Tradition (video). Rockville, MD, Na-
tional Criminal Justice Reference Service, 1995. Available at: http://www.ncjrs.gov/
App/publications/abstract.aspx?ID=164419. Accessed August 4, 2015.
Langan A: I am Angel of Death, warned college killer. Daily Telegraph, September 15,
2006. Available at: http://www.telegraph.co.uk/news/worldnews/1528946/I-am-
Angel-of-Death-warned-college-killer.html. Accessed January 8, 2015.
Link BG, Phelan JC, Bresnahan M, et al: Public conceptions of mental illness: labels,
causes, dangerousness, and social distance. Am J Public Health 89(9):1328–1333,
1999 10474548
Martone CA, Mulvey EP, Yang S, et al: Psychiatric characteristics of homicide defen-
dants. Am J Psychiatry 170(9):994–1002, 2013 23896859
Marzuk PM, Tardiff K, Hirsch CS: The epidemiology of murder-suicide. JAMA 267(23):
3179–3183, 1992 1593740
Meloy JR, Hoffmann J (eds): International Handbook of Threat Assessment. New York,
Oxford University Press, 2014
Meloy JR, O’Toole ME: The concept of leakage in threat assessment. Behav Sci Law
29(4):513–527, 2011 21710573
Meloy JR, Hoffman J, Guldimann A, et al: The role of warning behaviors in threat assess-
ment: an exploration and suggested typology. Behav Sci Law 30(3):256–279, 2011
Metzl J, Macleish K: Mental illness, mass shootings, and the policies of American fire-
arms. Am J Public Health 105(2):240–249, 2015
Mills J, Kroner D, Morgan R: Clinician’s Guide to Violence Risk Assessment. New York,
Guilford, 2011
Mitchell R: Dancing at Armageddon: Survivalism and Chaos in Modern Times. Chicago,
IL, University of Chicago Press, 2002
Modzeleski W, Feucht T, Rand M, et al: School-associated student homicides—United
States, 1992–2006. MMWR Morb Mortal Wkly Rep 57(2):33–36, 2008 18199965
Mullen PE: The autogenic (self-generated) massacre. Behav Sci Law 22(3):311–323,
2004 15211554
Neuman Y: On revenge. Psychoanalysis, Culture & Society 17:1–15, 2012
Newman KS, Fox C, Roth J, et al: Rampage: The Social Roots of School Shootings. New
York, Basic Books, 2005
Nichols A: Camera catches Omaha mall shooter. Daily News, December 8, 2007. Avail-
able at: http://www.nydailynews.com/news/world/camera-catches-omaha-mall-
shooter-article-1.273367. Accessed January 8, 2015.
Nielssen O, Bourget D, Laajasalo T, et al: Homicide of strangers by people with a psy-
chotic illness. Schizophr Bull 37(3):572–579, 2011 19822580
Norris D, Price M, Gutheil T, et al: Firearm laws, patients, and the roles of psychiatrists.
Am J Psychiatry 163(8):1392–1396, 2006 16877652
Orange R: Anders Behring Breivik’s sister warned mother about his behaviour two years
ago. Daily Telegraph, December 4, 2011. Available at: http://www.telegraph.co.uk/
news/worldnews/europe/norway/8934136/Anders-Behring-Breiviks-sister-warned-
mother-about-his-behaviour-two-years-ago.html. Accessed January 8, 2015.
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

Mass Shootings and Mental Illness 103
O’Toole ME: The School Shooter: A Threat Assessment Perspective. Quantico, VA, Na-
tional Center for the Analysis of Violent Crime, Federal Bureau of Investigation,
2000
O’Toole ME: A different perspective on the UCSB mass murder. Violence and Gender
1(2):49–50, 2014
Parker GF: Application of a firearm seizure law aimed at dangerous persons: outcomes
from the first two years. Psychiatr Serv 61(5):478–482, 2010 20439368
Phelan J, Link B, Stueve A, et al: Public conceptions of mental illness in 1950 and 1996:
what is mental illness and is it to be feared? J Health Soc Behav 41(2):188–207, 2000
Pies R: Everything Has Two Handles: The Stoic’s Guide to the Art of Living. Lanham,
MD, Hamilton Books, 2008
Pinals D, Appelbaum P, Bonnie R, et al: Resource Document on Access to Firearms by
People With Mental Illness. Arlington, VA, American Psychiatric Association, 2014
Pinker S: The Better Angels of Our Nature: Why Violence Has Declined. New York, Viking
Press, 2011
Preti A: School shooting as a culturally enforced way of expressing suicidal hostile inten-
tions. J Am Acad Psychiatry Law 36(4):544–550, 2008 19092074
Rodger E: My Twisted World (online), 2014. Available at: http://www.document-
cloud.org/documents/1173808-elliot-rodger-manifesto.html. Accessed January 8,
2015.
Saleva O, Putkonen H, Kiviruusu O, et al: Homicide-suicide—an event hard to prevent
and separate from homicide or suicide. Forensic Sci Int 166(2–3):204–208, 2007
16806773
Sandy Hook Lighthouse: Adam Lanza posted about “depression” on the day his mother
bought him a gun. Sandy Hook Lighthouse, January 18, 2014. Available at: http://
sandyhooklighthouse.wordpress.com/2014/01/18/adam-lanza-posted-about-
depression-on-the-day-his-mother-bought-him-a-gun/. Accessed January 8, 2015.
Schanda H, Knecht G, Schreinzer D, et al: Homicide and major mental disorders: a 25-
year study. Acta Psychiatr Scand 110(2):98–107, 2004 15233710
Schildkraut J, Muschert G: Media salience and the framing of mass murder in schools: a
comparison of the Columbine and Sandy Hook massacres. Homicide Stud
18(1):23–43, 2013
Selkin J: Rescue fantasies in homicide-suicide. Suicide Life Threat Behav 6(2):79–85,
1976 941206
Simpson JR: Bad risk? An overview of laws prohibiting possession of firearms by indi-
viduals with a history of treatment for mental illness. J Am Acad Psychiatry Law
35(3):330–338, 2007 17872555
Smith S, Shuy R: Forensic psycholinguistics: using language analysis for identifying and
assessing offenders. FBI Law Enforcement Bulletin 71(4):16–21, 2002
Spillane J: Myth, memory, and the American outlaw. Oral Hist Rev 26(1):113–117,
1999
Strauss D: Rubio supports “comprehensive study” of gun laws. The Hill, December 17,
2012. Available at: http://thehill.com/blogs/blog-briefing-room/news/273273-
rubio-supports-comprehensive-study-of-gun-laws. Accessed January 8, 2015.
Swanson JW: Preventing the unpredicted: managing violence risk in mental health care.
Psychiatr Serv 59(2):191–193, 2008 18245162
Swanson JW, McGinty EE, Fazel S, et al: Mental illness and reduction of gun violence
and suicide: bringing epidemiologic research to policy. Ann Epidemiol 25(5):366–
376, 2015 24861430
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.

104 GUN VIOLENCE AND MENTAL ILLNESS
Twenge JM, Campbell WK: “Isn’t it fun to get the respect that we’re going to deserve?”
Narcissism, social rejection, and aggression. Pers Soc Psychol Bull 29(2):261–272,
2003 15272953
Twenge J, Campbell WK: The Narcissism Epidemic: Living in the Age of Entitlement.
New York, Atria Books, 2009
Twenge JM, Konrath S, Foster JD, et al: Egos inflating over time: a cross-temporal meta-
analysis of the Narcissistic Personality Inventory. J Pers 76(4):875–902, discussion
903–928, 2008 18507710
Twenge JM, Campbell WK, Freeman EC: Generational differences in young adults’
life goals, concern for others, and civic orientation, 1966–2009. J Pers Soc Psychol
102(5):1045–1062, 2012 22390226
Vossekuil B, Fein R, Reddy M, et al: The Final Report and Findings of the Safe School
Initiative: Implications for the Prevention of School Attacks in the United States.
Washington, DC, U.S. Department of Education, Office of Elementary and Second-
ary Education, Safe and Drug-Free Schools Program, and U.S. Secret Service, Na-
tional Threat Assessment Center, 2002
Warren LJ, Mullen PE, Ogloff JR: A clinical study of those who utter threats to kill. Behav
Sci Law 29(2):141–154, 2011 21374705
The Washington Post: Remarks from the NRA press conference on Sandy Hook school
shooting, delivered on Dec. 21, 2012 (transcript). WashingtonPost.com, December
21, 2012. Available at: http://www.washingtonpost.com/politics/remarks-from-
the-nra-press-conference-on-sandy-hook-school-shooting-delivered-on-dec-21-
2012-transcript/2012/12/21/bd1841fe-4b88-11e2-a6a6-aabac85e8036_story.html.
Accessed January 8, 2015.
Webster C, Haque Q, Hucker S: Violence Risk—Assessment and Management: Advances
Through Structured Professional Judgment and Sequential Redirections, 2nd Edi-
tion. London, Wiley-Blackwell, 2013
Copyright © 2016 American Psychiatric Association Publishing. All Rights Reserved.
To purchase the complete resource, please visit www.appi.org or your local bookseller.