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2 Understanding the Psychological Consequences of Traumatic Events, Disasters, and Terrorism Terrorism is intended to provoke collective fear and uncertainty. This fear can spread rapidly and is not limited to those experienc- ing the event directly others that are affected include family mem- bers of victims and survivors, and people who are exposed through broad- cast images. Psychological suffering is usually more prevalent than the physical injuries from a terrorism event. Understanding these psycho- logical consequences is critical to the nation's efforts to develop interven- tion strategies at the pre-event, event, and post-event phases that will limit the adverse psychological effects of terrorism. This chapter serves as a brief overview of the literature on traumatic events, disasters, and terrorism. It first reviews a sample of the literature on the psychological consequences of traumatic events and disasters. The chapter then describes the smaller body of research that specifically ex- amines the consequences of terrorist attacks and discusses how the conse- quences of terrorism may differ from other types of traumatic events. This chapter is not meant to represent a thorough review of the trauma and disaster literature; rather it is intended to highlight some of the salient and relevant findings that may direct responses to terrorism events. For a comprehensive review, the reader is referred to Holloway et al. (1997), Norris et al. (2002a, 2002b), and Rub onis and Bickman (1991~. TRAUMATIC EVENTS The effect of traumatic events on human functioning has been a sub- ject of study for many years. An abundance of research has examined 34
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 35 traumatic events ranging from individual events such as motor vehicle crashes and sexual assaults to community-wide events such as natural disasters, commercial airplane crashes, and community violence, as well as global events such as war. As defined by the The Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV), a traumatic event or witnessing such an event triggers fear, helplessness, or horror in response to the perceived or actual threat of injury or death to the individual or to an- other (APA, 1994~. Traumatic events are usually perceived by the indi- vidual to be life-threatening, unexpected, and infrequent, and are charac- terized by high intensity (Ursano et al., 1994~. However, traumatic events may be repeated within a community, and in such environments the pres- ence of a threat may become the norm. Evidence suggests that the type and severity of outcomes often vary according to the type of event (Freedy and Donkervoet, 1995~. The effect of exposure to a traumatic event is variable and specific to the individual; both psychological and physiological responses can vary widely. Social context, biological and genetic makeup, past experiences, and future expectations will interact with characteristics of the traumatic experience to produce the individual's psychological response (Ursano et al., 1992~. In general, those exposed to a traumatic event show increased rates of acute stress disorder, posttraumatic stress disorder (PTSD), major depression, panic disorder, generalized anxiety disorder, and substance use disorder (Kessler et al., 1995~. Although psychiatric illnesses such as PTSD are the more severe outcomes of traumatic events, they are also the best studied. Much of the research literature has focused specifically on PTSD because it is a recognized and well-defined result of traumatic events (see Box 2-1~. However, PTSD is just one outcome in a myriad of consequences resulting from traumatic events. Spectrum of Consequences of Traumatic Events The experience of a traumatic event does not necessarily lead to seri- ous psychological difficulties. As discussed in Chapter 1, there is a spec- trum of consequences ranging from distress responses such as mild anxi- ety, to behavioral changes such as mild difficulty sleeping, to the onset of a diagnosable psychiatric illness (see Figure 1-2~. These consequences generally can be placed into three categories of severity, which may also correspond to strategies for intervention: · The majority of people may experience mild distress responses and/or behavioral change, such as insomnia, feeling upset, worrying, and increased smoking or alcohol use. These individuals will likely recover
36 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 37 with no required treatment, but may benefit from education and commu- nity-wide supportive interventions. · A smaller group may have more moderate symptoms such as per- sistent insomnia and anxiety and will likely benefit from psychological and medical supportive interventions. · A small subgroup will develop psychiatric illnesses such as PTSD or major depression and will require specialized treatment. The number of people experiencing each of these outcomes varies di- rectly with the severity of the event and with proximity of exposure to it. Most people will experience mild or infrequent symptoms, while only a few may experience frequent and/or severe symptoms. Because terrorist attacks may cause violent injury, death, and destruction, there often will be a targeted population that experiences extreme trauma, a widening group of family members and friends who are also therefore directly af- fected, and an even larger community and societal population who are confronted with the danger of terrorism through the media and on a daily basis. Furthermore, the relative number of people in any one of these categories is based not only on the population but also characteristics of the event itself. Figure 2-1 provides a conceptual illustration of this rela- tionship between proximity and severity, and outcomes; it should be kept in mind that this curve is theoretical and proportions will change in some situations. The association between severity and/or number of symptoms and the number of people affected is important to consider when planning interventions in the aftermath of a community-wide disaster or terrorism event. The severity and diagnostic constellations of symptoms will dic- tate what treatment or intervention, if any, is needed. People with mild symptoms may expect fairly rapid resolution of their symptoms and may require fairly simple interventions and/or support, such as appropriate risk communication messages from the media and public health commu- nity explaining that these symptoms are normal, expected reactions to the experience of a traumatic event. The minority of people with severe symp- toms and/or psychiatric illness may require conventional treatment from the mental health system. This highlights the need for coordination and collaboration between the public health and mental health communities in order to address the needs of diverse populations across the spectrum of symptoms and manifestations. Traumatic Events in Children and Adolescents The childhood experience of traumatic events induces immediate bio- logical and psychological reactions, some of which may persist for an ex-
38 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM Many c' Q To Q To Q A Few Examples of mild reactions: · Insomnia · Worry · Feeling upset - Examples of moderate reactions: · Persistent insomnia · Anxiety - Examples of severe reactions: · PTSD · Depression Mild/Few Severity or number of symptoms Severe/Many - FIGURE 2-1 Severity of psychological reactions experienced by the population following a traumatic event. NOTE: Indicative only. tended period. The psychological symptoms of traumatic events in chil- dren and adolescents are similar to those recognized in adults, but often appear as age-appropriate expressions of the stressful event. See Box 2-2 for examples of possible reactions of children to traumatic events. Youth who have been exposed to violence have been more likely to develop psychological problems and have poor functioning at home and school (Cohen, 1998; Pynoos et al., 1995; Richters and Martinez, 1993~. Recent studies indicate that about one-third of children exposed to com- munity violence develop PTSD (Berman et al., 1996; Fitzpatrick and Boldizar, 1993~. Youth exposed to traumatic events also can develop de- pression, other anxiety disorders, substance use disorders, and problems with school performance (Brent et al., 1995; Clarke et al., 1995; Saigh et al., 1997; Singer et al., 1995; Weine et al., 1995~. Widespread negative psycho- logical effects have also been reported following acts of violence on high school campuses, such as the school shootings at Columbine High School in Littleton, Colorado, and Santana High School in Santee, California. Biological research has demonstrated that, like adults, children ex- posed to traumatic events show alterations in stress hormone systems. However, a unique difference among children is the association of expo- sure to traumatic events with measurable discrepancies in neurophysi-
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 39 ological development. It is believed that prolonged levels of significant stress may adversely affect the neurophysiological development of young children in ways that may have long-term consequences for behavioral responses to stress and later psychiatric illness (for reviews, see De Bellis, 2001; Glaser, 2000~. It is difficult to draw definitive conclusions from this research, however, since findings are frequently confounded with preex- isting risk factors for experiencing a traumatic event that are also associ- ated with differences in brain physiology.
40 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM DISASTERS A subset of the broader trauma literature has focused on the psycho- logical consequences of disasters. Disasters differ from other forms of traumatic events in that, by definition, they are likely to affect larger seg- ments of the population or entire communities of individuals, causing widespread destruction and distress. Spectrum of Consequences of Disasters Comprehensive reviews of the literature have consistently revealed a wide range of adverse outcomes following disasters (see, for example, Katz et al., 2002; Norris et al., 2002b; Rubonis and Bickman, 1991; Solomon and Green, 1992~. Results of a review of 49 research articles and books conducted by Solomon and Green (1992) revealed that most authors re- ported negative psychological consequences of disasters. Norris and col- leagues (2002b) reviewed 177 articles that examined 80 different disas- ters.~ The authors organized the most frequently documented negative sequelae of disasters into five categories: · Specific psychiatric illnesses (for example, PTSD, depression) · Nonspecific distress (symptoms without a specific diagnosis, such as demoralization, perceived stress, and negative affect) · Health problems and concerns (for example, somatic complaints, sleep disruption, increased use of sick leave) · Chronic problems in living (for example, social disruption, fam- ily conflict, financial and occupational stress) · Psychosocial resource loss (for example, decreases in social par- ticipation and perceived support) The authors suggest that children were the segment of the population at greatest risk for psychological trauma, behavioral changes, and impair- ment. Research suggests that disasters experienced at a younger age may have long-term psychological consequences. One study followed a group of adolescents who experienced the sinking of a ship, and found that more than a third of those adolescents who developed PTSD subsequent to the disaster still had PTSD at either five or eight years follow-up (Yule et al., 2000~. ~ Norris et al. (2002a, 2002b) included in their sample disasters due to "mass violence." These types of disasters comprised 9 percent of their sample, and may include acts of terrorism.
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 41 It is important to note that many psychological reactions to disasters are considered ordinary responses to stress. For example, almost half of the survivors of an earthquake in Northridge, California, exhibited dis- tress symptoms of reexperiencing the disaster and hyperarousal, but these symptoms alone were not associated with psychiatric illness and were considered "normal" (McMillen et al., 2000~. Regardless of psychi- atric illness, it is critical to consider functional impairment when evaluat- ing the psychological consequences of a disaster or other traumatic event. Box 2-3 presents examples of other ordinary and expected psychological responses to a disaster. In addition to psychiatric illness and distress reactions, experiencing a disaster may result in alterations in health-related behaviors and produce general life changes. Substance use is one health-related behavior com- monly thought to increase in the aftermath of a disaster. Cigarette smok- ing and alcohol use may increase in individuals with PTSD after any kind of traumatic event (Shalev et al., 1990~. In their extensive review of disas- ter studies, Norris and colleagues (2002b) observed increased substance use in 25 percent of the populations under study. However, increased substance use does not necessarily develop into substance use disorders, and Katz and colleagues (2002) noted that only a small number of studies have looked at substance use as an outcome. Family interactions consti- tute another area of behavior that may be influenced by disasters. For example, Adams and Adams (1984) found increased domestic violence and family problems in a population of survivors of the Mount Saint Helens eruption. Family relationships and other social variables are an area not as frequently studied as other areas discussed here and are in need of further investigation. Evidence suggests that adverse psychological consequences of disas- ter dissipate over time for the majority of people. The studies included in Norris and colleagues' review suggested that symptoms measured shortly after the disaster were predictive of symptoms at subsequent points in time, and the greatest severity of symptoms was usually experienced within one year following the disaster; only a minority of disaster survi- vors had any significant and persistent impairment after the first year. Moderators of Adverse Outcomes After Disasters As discussed, many of the initial reactions to disasters can be consid- ered ordinary distress responses to traumatic events and the symptoms will dissipate over time. Thus, in order to intervene appropriately, it is important to be able to predict which individuals may experience long- term and serious consequences and to estimate the number of individu- als that may be affected. Predictors of long-term impairment after a di-
42 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 43 saster include many of those observed in other traumatic events. Mod- erators of adverse outcomes have been categorized into pre-event, event, and post-event phases that are consistent with the event phases described in Chapter 1. Pre-Event. Female gender has been associated with poorer outcome fol- lowing disasters, as has low socioeconomic status and minority status. The risk of PTSD after a disaster is also increased by the presence of a predisaster history of psychiatric illness (Smith et al., 1990; Yehuda, 2002) and particularly by a history of depression (Shalev et al., 1998~. However, Bromet et al. (1982) found no significant difference in mental health out- comes between patients with a psychiatric illness who experienced the Three Mile Island disaster and a control group. Event. Traditionally, mental health research has classified disasters into two categories: natural and human-caused (the latter includes techno- logical disasters such as hazardous materials spills, aviation disasters, ter- rorism, and even acts of war) (see Figure 2-2~. Although these categories are not always mutually exclusive, as dem- onstrated in Figure 2-2,3 there is some evidence to suggest that individual responses to disaster may vary depending on the type of event. While research in this area has typically examined natural disasters versus hu- man-caused disasters, there is no consensus regarding which events may produce a specific type of response. For example, North and Smith (1990) suggested, based on a review of the disaster literature, that human-caused disasters may result in higher rates of diagnosable psychiatric illnesses, and others have reported that human-caused disasters result in more per- sistent psychopathology (Baum, 1990; Green et al., 1990; Solomon and Green, 1992~. Conversely, Rub onis and Bickman (1991) concluded in their review of 52 studies that human-caused disasters resulted in less severe psychopathology than natural disasters. As shown in Figure 2-2, a distinction can be made between inadvert- ent human-caused disasters such as those caused by error or neglect and 2 Other typologies categorize disasters differently. One alternative uses three categories: natural events, technological events, and willful human acts including terrorism. 3 An example of a disaster that would fall into the area of overlap between human-made and natural disasters is the 1972 Buffalo Creek Flood. This disaster was caused by a combi- nation of heavy rains and poorly constructed dams. For a discussion of the "blurring" be- tween the distinctions of naturally occurring and human-made disasters, see Weisaeth (1994~. 4 Psychopathology was defined as any psychological problems, pathologies, or impairment suffered by victims of disasters.
44 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM Disasters Human-caused - / - - Tl Error or neglect - errorlsm I - FIGURE 2-2 Categories of disaster. SOURCE: Ursano (2002~. Natural - \ / intentional human-caused disasters such as those due to terrorism or mass violence. These two types of human-caused disasters may each lead to different types and severity of psychological consequences. However, research examining this issue is limited. The review by Norris et al (2002b) used a slightly different classification by disaster type with three catego- ries: natural; technological (for example, oil spills, transportation acci- dents); and mass violence (for example, shooting sprees, mass suicides, terrorism). Mass violence events were significantly more likely to result in severe impairment in the populations under study than either techno- logical or natural disasters. Therefore, although research shows that all types of disasters, including intentional and inadvertent human-caused disasters, may cause psychological distress, behavior change, or psychiat- ric illness to different degrees, additional studies should identify the mechanisms and specific characteristics leading to adverse outcomes. Norris and colleagues (2001) propose that when at least two of the following four characteristics of disasters are present, the mental health impact will be greatest: Widespread damage to property · Serious and ongoing financial problems · Human error or human intent that caused the disaster · High prevalence of trauma (injuries, threat to life, loss of life) With the exception of "serious and ongoing financial problems," these important characteristics of disaster experiences are specific to the event phase. Understanding how specific aspects of disasters relate to specific
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 45 outcomes will help facilitate planning for mental health interventions in the aftermath of disasters. Post-Event. The presence or absence of psychosocial support is signifi- cantly associated with outcomes. When people feel that they have been neglected or forgotten by their government or community, they are more likely to have long-term adverse effects from a disaster experience (Norris et al., 2002b). In addition, as mentioned above, ongoing financial stress, job loss, and other post-event negative occurrences are associated with more severe adverse psychological consequences. Positive Psychosocial Consequences Although less well documented than the negative effects, the experi- ence of a disaster or other traumatic event may result in a positive impact on both individuals and the community. A small but growing literature exists on the process of posttraumatic growth, describing the develop- ment of adaptive coping mechanisms and feelings of self-efficacy follow- ing exposure to traumatic events (e.g., Calhoun and Tedeschi, 2001~. Thus, the experience of a traumatic event can also promote resilience for future traumatic events. The communal experience of overcoming a disaster may promote greater community cohesion. Altruism and volunteerism frequently in- crease in the aftermath of a disaster. These are phenomena that can be beneficial both to those receiving the assistance and to those who volun- teer, since the perception of self-efficacy and the ability to "do something" can help people to cope with the disaster experience. TERRORISM Terrorism, a subset of human-caused disasters (Figure 2-2), can have a particularly devastating impact on psychological functioning. Terror- ism carries with it a potentially greater impact than other disasters on distress responses, behavioral change, and psychiatric illness by virtue of the unique characteristics of terrorism events (see Table 2-1~. Terrorist attacks, and the threat of a terrorism event, may also result in more severe psychological consequences than other types of traumatic events due to a perceived lack of control. Perceptions of risk are influ- enced by the degree to which individuals feel they have knowledge of and control over an outside event and how familiar and catastrophic the event will be (for review, see Slovic, 1987~. People are more likely to feel that an activity or event is not dangerous if they can control it. Under these circumstances, it becomes less effective to cope by distancing
46 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM TABLE 2-1 Characteristics of Disasters of Different Etiologies Etiology Human-Caused Characteristics Natural Error or Neglect Terrorism Intent Not present Not present Present intended to threaten and/ or incite fear Predictability Possibly, where disasters are cyclic in nature Possibly, where there Largely is a hazard site unpredictable; possible where there is a target of symbolic value Preventability May not be possible, May be possible with May be possible but warning may training and vigilance with security and limit impact monitoring of terrorist activity Societal disruption of normalcy and safety Local Present Present Present General May be present May be present Present Resultant sense of Present Present Present vulnerability Impact on emergency providers Directly involved Present Indirectly involved May be present Impact on special May be present groups Emergency, medical public health, and psychological management Pre-event Present May be present May be present Present Present Present preparedness Necessary Necessary Necessary Event response Necessary Necessary Necessary Post event recovery Necessary Necessary Necessary
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 47 oneself from the population at risk if the risk is seemingly random. For example, the degree of public anxiety resulting from the 2001 Washing- ton, D.C., area sniper attacks was much greater than the anxiety levels related to the violence that is endemic to many Washington, D.C., areas. The event affected many people in the region for weeks. It was easier for people to distance themselves from urban violence (which is controllable by staying away from urban centers) than from the sniper attacks that were perceived as more threatening and random than everyday shootings. In addition to its distinctive characteristic of intent, terrorism can uniquely disrupt societal functioning. Terrorism has the capacity to erode the sense of community or national security; damage morale and cohe- sion; and open the racial or ethnic, economic, and religious cracks that exist in our society, as evidenced by an increase in hate crimes following ~ , ~ ~ ~ ~ the September 11, 2001, attacks (Human Rights Watch, 2002; FBI, 2002~. Spectrum of Consequences of Terrorism Following a terrorism event, most people will experience stress- related symptoms across the spectrum of psychological responses as il- lustrated earlier in Figure 2-1. Many of the psychological consequences of terrorism are similar to those seen in the aftermath of other disasters. However, the literature specific to the psychological sequelae of terrorist attacks is much more limited in both prevalence and detail than that re- lated to other types of disasters. Similar to research in the broader trauma field, most of these studies have focused on PTSD or symptoms of PTSD as outcomes. Less is known about other, nonpathological outcomes. It is often difficult to compare studies because of the use of varying and previ- ously unvalidated measurement instruments. Furthermore, the signifi- cance of selected PTSD symptoms for determining longer-term function- ing is unclear. Methodological issues regarding this line of research are discussed further at the conclusion of this chapter. A review of the psy- chological consequences of terrorist attacks by Gidron (2002) found six studies that met his criteria for inclusion.5 In this review, Gidron calcu- 5 These criteria were: inclusion of subjects who were direct victims of terrorist attacks (terrorist attack defined as a "deliberate human-made violent event with a political mo- tive"~; subjects assessed with reliable PTSD instruments or with instruments based on DSM criteria; studies published in English between 1980 and 2001. The six studies that met the criteria were: Abenhaim et al., 1992; Amir et al., 1998; Curran et al., 1990; Shalev, 1992; Trapler and Friedman, 1996; Wilson et al., 1997. A summary of results from each of these studies can be found in Table 2-2.
48 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM TABLE 2-2 Sample of Research on Psychological Consequences of Terrorism Events Event Year Morbidity or Outcome Reference New York City (NYC) 2001 and Arlington: World Trade Center and the Pentagon Israel: attack on 1996 women on bus 7.5% of NYC residents had symptoms of acute PTSD, and 9.7% had depression at 5-8 weeks after attacks; 20% of those closest to the attack site had symptoms of acute PTSD Galea et al., 2002 Utilization rates of antianxiety medications were significantly Goldman, 2002 higher than expected during October 2001. No significant effects were seen for antidepressant medication utilization 44% of a nationally representative sample reported one or more "substantial stress symptom" Rate of "probable PTSD" higher in NYC (11.2%) than elsewhere in the US (4%) 1-2 months after attacks 17% of a nationally representative sample reported symptoms of posttraumatic stress 2 months after the attacks; 5.8%, at 6-month follow-up 9.7% of Manhattan residents reported an increase in smoking, 24.6% reported an increase in alcohol consumption, and 3.2% reported an increase in marijuana use 5-8 weeks after the attacks Schuster et al., 2001 Schlenger et al., 2002 Silver et al., 2002 Vlahov et al., 2002 27% diagnosed with PTSD Amir et al., 1998 after treatment intervention consisting of group debriefing with brief group psychotherapy
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES TABLE 2-2 Continued 49 Event Year Morbidity or Outcome Reference Oklahoma City: 1995 Fear during event and feeling Tucker et al., 2000 bombing that treatment was helpful were associated with higher risk of PTSD among adults seeking help Children, especially girls, who Peak, 2000 knew someone who died or who was injured in the bombing had more severe PTSD symptoms than those that did not know victims 45% of sample of survivors of direct blast had one or more psychiatric illnesses; 34% had PTSD Degree of television and emotional exposure was associated with posttraumatic stress symptoms among middle school students Tokyo, Japan: sarin 1995 gas released in subway NYC: shooting at van 1994 of Hasidic Jews North et al., 1999 Pfefferbaum et al., 2001b Somatic and psychological symptoms present at 2-, 3-, and 5-year follow-up 8 of 34 victims developed PTSD after the attack Symptoms of distress present in exposed individuals at 1-, 3-, and 6-month follow-up Kawana et al., 2001 Tochigi et al., 2002 Ohbu et al., 1997 4 of 11 survivors diagnosed Trappler & with PTSD and comorbid Friedman, 1996 major depression Ireland: various 1993-1994 5% of police officers exposed to Wilson et al., 1997 terrorism events terrorist-related critical incidents had PTSD at 7-10- month follow-up continued on next payee
50 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM TABLE 2-2 Continued Event Year Morbidity or Outcome Reference Israel: attack on ~1990 civilian bus Enniskillen, Ireland: 1987 bombing France: various 1982-1987 terrorism events Chowchilla, CA: school bus kidnapping 1976 33% of sample had PTSD at 10-month follow-up. Early PTSD symptoms were not predictive of later diagnosis 50% of sample had PTSD at 6-month follow-up. There was no correlation with the degree of physical injury. More females than males had PTSD Shalev, 1992 Curran et al., 1990 PTSD present in 10.5% of Abenhaim et al. uninjured victims, 8.3% of 1992 moderately injured, and 30.7% of severely injured. Overall, 13.3% were diagnosed with major depression. No gender differences All of the 23 children in the Terr, 1981; 1983 kidnapping exhibited symptoms of posttraumatic stress at 5-13 months, and at 4 years follow-up. Brief treatment at 5-13 months did not prevent later symptoms fated the rate of PTSD for those who were directly exposed to a terrorist attack to be 28.2 percent. Given that the terrorist attacks on the World Trade Center and the Pentagon on September 11, 2001, in addition to di- rectly impacting thousands of people, may have had more than 100,000 direct witnesses (Schuster et al., 2001) and that millions across the country experienced the events through repeated media depictions, it can be pre- sumed that the impact of these events was quite significant. Table 2-2 presents significant findings from a selected set of studies examining a range of terrorism events. Studies taking place outside of the United States have frequently used similar designs to those within the United States, often focusing on PTSD or symptoms of PTSD. Although limited in number, these international research efforts add useful information to the knowledge-base on psycho- logical consequences of different types of terrorism events. In general, findings regarding the psychological sequelae of terrorist attacks are simi-
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 51 tar to those seen in United States-based studies; commonly reported ef- fects include PTSD and symptoms of PTSD, major depression, and gen- eral psychological distress as determined by various measures. Some of these studies also provide unique perspectives because they have been carried out on populations that have been exposed to varying forms of terrorism events such as smaller-scale bombings and shooting attacks (e.g., Abenhaim et al., 1992; Wilson et al., 1997) and a chemical attack (Kawana et al., 2001; Ohbu et al., 1997; Tochigi et al., 2002), while much of the body of research from the United States has focused on large explo- sive attacks. Two of the most significant acts of terrorism in the United States, the 1995 Oklahoma City bombing and the attacks of September 11, 2001, prompted a small, but growing, literature on psychological consequences of terrorism in this country. Research on the Oklahoma City bombing revealed PTSD in approximately one-third of survivors of the direct bomb blast six months after the bombing, and nearly three-fourths of these were individuals with no prior history of PTSD (North et al., 1999~. North and colleagues (1999) identified a specific constellation of symptoms that was highly predictive of PTSD. Avoidance and numbing symptoms were much more common among Oklahoma City bombing survivors with PTSD. In contrast, the symptoms of intrusive reexperience and hyper- arousal were "nearly universal" among survivors and were not predic- tive of PTSD when occurring by themselves. Several studies conducted after the Oklahoma City bombing focused on an adolescent population from the Oklahoma City Public School Dis- trict. More than 40 percent of the middle school students who partici- pated in one survey reported that they knew someone who was injured in the bombing, while more than 30 percent knew someone who was killed. Seven weeks after the bombing, 14.6 percent of the youth reported not feeling safe and 34.1 percent reported worrying about themselves or their families (Pfefferbaum et al., 1999~. This survey of middle school students also found that television and emotional exposure to the terrorism event was associated with posttraumatic stress symptoms (Pfefferbaum et al., 2001b). School officials in Oklahoma City reported a 25 percent decrease in attendance in the first weeks following the bombing. Students' initial apprehension about returning to school was shared by parents who sought evidence of better protective measures (Won", 2001~. Teachers and school administrators became concerned about their ability to iden- tify future perpetrators and to ensure the safety of students and staff. A number of authors have investigated the impact of the terrorist at- tacks of September 11, 2001, on the United States population in general and on New York City residents specifically. Galea and colleagues (2002) examined PTSD symptoms in New York City residents one to two months
52 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM after the attack. Results indicated that 7.5 percent of Manhattanites re- ported criterion symptoms of PTSD that were then used to estimate the prevalence of the disorder, while 20 percent of those near the World Trade Center at the time of the attacks reported such symptoms. Schlenger and colleagues (2002) studied a nationally representative cross-sectional sample one to two months after the attacks using self-reported symptoms of PTSD and general psychological distress to measure what they termed "probable PTSD." They found that residents of the New York City metro- politan area had the highest rate of probable PTSD in the country at 11.2 percent; the rate in the Washington, D.C., metropolitan area was 2.7 per- cent, in other major metropolitan areas 3.6 percent, and across the rest of the country 4.0 percent. A similarly designed nationally representative study by Silver and colleagues (2002) found that two months after the attacks, 17 percent of the country (not including those residing in New York City) had symptoms of September llth-related posttraumatic stress, while at six months, this number decreased to 5.8 percent. The discrep- ancy between the rates found by these two studies (4 percent versus 17 percent) likely reflects the different methodologies and populations used to estimate posttraumatic stress. In a national telephone survey conducted immediately after September 11, 2001, Schuster et al. (2001) measured the presence of various symptoms of distress responses. The symptoms re- ported by adults included feeling very upset when reminded of the events (30 percent), having trouble falling or staying asleep (11 percent), and feel- ing irritable (9 percent). A large study commissioned by the New York City Board of Educa- tion examined the psychological consequences of the September 11, 2001, terrorist attacks on 8,266 public school students in grades 4-12 through- out the five boroughs of New York City six months after the attacks (Hoven et al., 2002~. Results indicate widespread distress responses and symptoms of psychiatric illness that were not limited to students in prox- imity to the World Trade Center. Prevalence rates of symptoms such as those related to PTSD, generalized anxiety disorder, and separation anxi- ety were significantly higher than would be expected in children not ex- posed to a traumatic event. However, because pre-event baseline data are not available for the children surveyed, it is difficult to ascertain whether these findings reflect exposure to the terrorism event or other features of the population. Similar to findings in the disaster mental health literature, some evi- dence indicates that terrorism events may lead to increases in substance use. One survey of residents of New York, Connecticut, and New lersey found that 21 percent of cigarette smokers reported an increase in smok- ing after the attacks (Melnik et al., 2002~. Similarly, Vlahov and colleagues (2002) reported increases in substance use, including alcohol, in New York
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 53 City and the surrounding areas in the months after September 11, 2001. In comparison, a study of survivors of the Oklahoma City bombing found no new cases of diagnosable substance use disorder subsequent to the attack (North et al., 1999~. It is important to make a distinction between increases in substance use and substance abuse. Data indicating a simple increase in alcohol or tobacco use do not necessarily indicate problematic or long-standing behavior changes. Other behaviors and outcomes reflecting functional impairment after terrorism events are in need of further study. School dropout rates, di- vorce, and domestic or interpersonal violence and conflict are potential future research topics in this area. Increases in school or work absentee- ism, which may indicate functional impairment, have been noted follow- ing terrorist attacks. A survey by Melnik and colleagues (2002) found that 27 percent of respondents who were working in New York City at the time of the September 11,2001, attacks missed work in the following days. This was due primarily to transportation problems caused by increased security measures such as surveillance of bridges and tunnels leading into Manhattan. Increased absenteeism from work or school has also been reported after other violent events. For example, during the serial sniper attacks in the Washington, D.C., metropolitan area in October 2002, a sig- nificant increase in school absences occurred, with attendance rates as low as 10 percent at several elementary schools near one of the shooting sites (Schulte, 2002~. However, this behavior may be considered an appropri- ate response rather than a distress response because one of the victims of the sniper was a child who was shot while walking from a car into a school. A similar distinction can be made when looking at behavioral responses to the anthrax attacks of 2001. An average citizen using gloves to open mail may have been considered to manifest an adverse behavioral change related to psychological distress. However, if the person was a staff member in one of the offices specifically targeted in the anthrax mail- ings, the use of gloves might be considered an appropriate response. Health care seeking by individuals who are not actually at risk or injured, but seek health care due to fear and anxiety, has been observed in response to terrorism events. This phenomenon was noted following the satin poisoning in the Tokyo subway and during the anthrax attacks in the fall of 2001 when tens of thousands of people who were not at risk for exposure obtained prescriptions for the antibiotics ciprofloxacin and doxycycline (Shaffer et al., 2003~. Accurate and timely risk communica- tion becomes particularly important in limiting the potential stress on the health care system because unaffected individuals flood services. This type of behavior is most likely to occur in the event of chemical, biologi- cal, radiological, or nuclear attack and is discussed further below in the section detailing the consequences of these types of terrorism.
54 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM Moderators of Adverse Outcomes after Terrorist Attacks: Identifying Vulnerable Populations Research from the disaster mental health field has developed models that stratify groups based on exposure level. These levels include those indirectly or remotely affected individuals who are not in close geographic proximity to the incident, but who witness the event through the media; those who are negatively exposed through secondary effects such as an economic downturn; and those who experience the death of or immediate risk to a loved one from the terrorism event (i.e., relatives, friends, co- workers, rescue workers, witnesses). The populations that will be directly affected may vary according to the type of event (e.g., bombing; hijacking; chemical, biological, radiological, or nuclear attack). For example, a bio- logical attack on the U.S. food supply may have a direct impact on agri- cultural workers through both physical and economic effects, and the re- sulting disruption may have an indirect impact on society as a whole. Given the large number of individuals, from those remotely to those di- rectly exposed, who may be affected by a terrorism event, it is important to recognize variations among these exposed subpopulations in order to identify those who are most vulnerable to the psychological consequences of the event. This will allow for the focus of limited resources on preven- tion and intervention for those most in need. Virtually all members of communities affected by terrorism are vul- nerable to negative psychological outcomes. The type of vulnerability may vary substantially and may not always be obvious. Diverse vari- ables that may enhance the prediction of adverse outcomes following a terrorism event are presented below in pre-event, event, and post-event temporal categories. Pre-Event. Shalev (2001) reviewed a previously conducted meta-analysis examining predictors of adverse outcomes for traumatic events in general and concluded that preexisting factors have less influence on an indi- vidual than the disaster itself and subsequent factors such as community support. Some models of response propose that the impact of pre-exist- ing factors is confounded with the dose of exposure; when the dose is less, the impact of pre-existing factors is more evident, and as the magnitude of the event increases, pre-event characteristics become less important. Regardless, these preexisting factors are useful to consider when plan- ning service delivery because they allow for a better understanding of those who may be at increased risk and require particular attention. Gender, age, experience, and personality have all been implicated in moderating adverse outcomes. Female gender has been associated with worse short-term outcomes in a number of studies of the general popula-
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 55 lion after September 11,2001 (e.g., North et al., 1999; Schlenger et al., 2002; Silver et al., 2002~. Prior marital separation and preexisting physical ill- ness have also been implicated in predicting greater psychological dis- tress after these events (Silver et al., 2002~. As in studies of disasters, the pre-event experience of traumatic events may be related to psychological consequences following terrorism events. For example, the investigation of New York City public school students after September 11,2001, found that nearly two-thirds of the students sur- veyed reported one or more prior traumatic events such as seeing some- one killed or seriously injured and experiencing the violent or accidental death of a family member. In this sample, a history of prior traumatic events was associated with significantly increased rates of symptoms con- sistent with PTSD (Hoven et al., 2002~. It is difficult, however, to discern the relative contributions of the prior traumatic events and the actual ter- rorism event to the reported symptoms given the lack of pre-event baseline data in this population. Age has been identified as possibly moderating psychological re- sponses to terrorism. While several studies examining adult populations have found no significant influence of age on the severity of psychologi- cal responses to terrorist attacks (e.g., Abenhaim et al., 1992), the psycho- logical impact of terrorist attacks on children and adolescents is frequently noted as an area of concern as described above. One study reported that students in the fourth and fifth grades were significantly more likely than those in grades six through twelve to endorse symptoms consistent with PTSD after the September 11, 2001, terrorist attacks (Hoven et al., 2002~. Further research is needed to determine if children and adolescents are at greater risk for psychological consequences than adults. The disaster literature has also identified ethnic and racial minority status as a potential moderating factor on adverse outcomes. Norris and colleagues (2002b) reviewed studies that included ethnicity as a variable and found that among adults, ethnic majority groups had better outcomes after disasters than minorities in all of the samples. Among youth, how- ever, the results were more variable. The research base examining racial and ethnic minority status as a factor predicting outcomes to terrorism events is extremely limited, although a few studies provide some indica- tion. For example, Galea et al. (2002) found that Hispanic ethnicity pre- dicted symptoms consistent with both PTSD and depression among Man- hattan residents after the September 11, 2001, terrorist attacks. Similar results were found among New York City public school students after those attacks; Hispanic students were more likely than either African- American, white, or Asian students to have symptoms of PTSD (Hoven et al., 2002~.
56 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM Findings from the disaster mental health literature have indicated that first responders and rescue workers are a population at risk for adverse psychological outcomes after responding to disasters (e.g., Duckworth, 1986; Tones, 1985; Weiss et al., 1995), likely due to their direct and often ongoing exposure to traumatic experiences. Findings after terrorism events reveal similar results. One study of New York City Fire Depart- ment rescue workers found a seventeenfold increase in stress-related inci- dents (e.g., depression, anxiety disorders, bereavement issues) during the 11-month period following the September 11, 2001, attacks as compared to the 11-month period preceding the attacks (Banauch et al., 2002~. These data, however, may not represent the typical experiences of first respond- ers and rescue workers because of the deaths of so many fellow firefighters in the immediate aftermath of the attacks. North and colleagues (2002b) found a PTSD rate of 13 percent among rescue workers in Oklahoma City. PTSD was associated with more days spent working at the site and more time spent in the central bombing pit. However, this study compared rescue workers to primary victims of the bombings and found that PTSD was significantly lower among rescue workers. The authors speculated that this may be related to characteristics of rescue workers such as pre- paredness, experience with job-related traumatic events, and self-selec- tion for the type of work, as well as lower injury rates among rescue work- ers and exposure to education and debriefing aimed at mitigating psychological consequences (North et al., 2002b). Event. While it is clear that certain populations may be particularly vul- nerable to adverse outcomes following a terrorism event, there are factors related to the event itself that may affect the degree of impact. Findings from the disaster and other trauma literature have suggested that the du- ration and intensity of exposure to the traumatic event, including indirect exposures such as traumatic grief and loss, are some of the most impor- tant predictors of an adverse impact on subsequent functioning. Evidence suggests that terrorism events are similar to other traumatic events in this regard. As described earlier, psychological consequences will vary across the population in relation to the quality and extent of exposure: some people will experience direct physical trauma or threat of trauma; others, such as family members and friends, will experience grief and loss; and a wider population will be affected by secondary adversities and a general climate of fear. Silver and colleagues (2002) found that the degree of ex- posure to the September 11, 2001, attacks (as measured by a composite of proximity to the various attack sites, presence at a site, contact with a victim whether visually or by phone during the attacks, and degree of watching the events live on TV) was significantly predictive of psycho-
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 57 logical distress, more so than the degree of loss,6 although both exposure and degree of loss were associated with distress. Similarly, Schlenger et al. (2002) suggested that the amount of time spent watching television coverage predicted both PTSD symptomatology and general distress, al- though these authors were careful to note that this association did not necessarily imply causation (e.g., more symptomatic people could have been drawn to watching the television news coverage). See Box 2-4 for additional information on the role of the media during terrorism events. Other important event-related characteristics include the duration and type of attack. Unlike other disasters, terrorism events may manifest as a single massive attack (e.g., Oklahoma City bombing), multisite event (e.g., events of September 11, 2001), multisite continuous or repeated events (e.g., anthrax attacks of 2001), or continuous or repeated events (e.g., ter- rorist attacks in Northern Ireland) (Ursano,2002~. The mechanism or type of attack also may moderate outcomes. Biological and radiological at- tacks may involve considerable on-going exposure to the threat and de- layed emergence of physical symptoms, while an attack with conventional explosives will likely be a discrete event with obvious and more immedi- ate injuries. The effects of cyberterrorism events, which have not been adequately studied, are largely unknown. These characteristics of terror- ism events can determine the degree of population exposure, and the se- verity and magnitude of psychological consequences. Hoaxes and copycat events may initially result in psychological con- sequences similar to those of actual terrorism events. Although the re- search base is extremely limited, the psychological impact of a hoax may be as great as that of a true threat. For example, Dougherty, et al. (2001) examined the psychological impact on victims of two incidents of anthrax threats that were later determined to be hoaxes and found evidence of distress symptoms. Results revealed that victims frequently reported a number of posttraumatic stress symptoms even after the hoax was an- nounced. A similar relationship with adverse psychological consequences may exist with false alarms for terrorism events, although research in this area is also limited. False alarms and warnings that are given to people not at risk have implications for future preparedness and response since a "cry-wolf" syndrome may result in which people become less responsive to future warnings (NRC, 2002b). Post-Event. A number of post-event factors may also help identify those at increased risk for negative psychological outcomes. The investigation 6 Severity of loss was assessed using a 6-level continuum, with O indicating no loss; 1, property loss of someone close; 2, personal loss of property; 3, injury of someone close; 4, death of someone close; and 5, personal injury in the attacks.
58 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM by Galea and colleagues (2002) examining residents of Manhattan after the September 11, 2001, terrorist attacks found that post-event factors pre- dicting PTSD symptoms included panic attack during or shortly after the attacks, and loss of possessions due to the attacks. Similarly, post-event factors predicting depression included panic attack during or shortly af- ter the attacks, death of a friend or relative during the attacks, and job loss due to attacks. Although many people will exhibit some manifestation of distress in the aftermath of a terrorism event, several specific symptoms have been identified as being more predictive of later psychiatric illness. These symptoms include feeling numb, withdrawn, or disconnected; isolation from others; and avoiding activities, places, or people that bring back
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 59 memories of the event (North et al., 1999, see also Box 2-3~. It may be important to screen for these specific symptoms during the post-event period in order to identify individuals who may require mental health care. The ways in which people cope with the stress of a terrorism event is also predictive of later outcomes. Silver and colleagues (2002) found that those who used active copings had less distress than those who dem- onstrated denial, defeatism, and self-distraction indicating disengage- ment with coping had greater distress. Secondary and Community Consequences Because terrorism, unlike natural disasters or human-caused techno- logical failures, is a purposeful act by an individual or a group of indi- viduals, terrorist acts are often perceived to be perpetrated by a specific ethnic, racial, or religious group. Recently, debate has increased about the controversial practice of profiling based on these characteristics for law enforcement purposes in the identification of potential terrorists. In addition, discrimination or stigmatization of the identified racial, ethnic, or religious group are potential outcomes of such perceptions, and may constitute threats to community cohesion and to the psychological well- being of those who are the targets of discrimination. Community cohe- sion can decrease as neighbors become suspicious of strangers and of one another. A multiethnic and multicultural population might exacerbate these fears. After the terrorist attacks on September 11, 2001, the number of hate crimes against Arabs, Muslims, and those perceived to be Arab or Muslim rose sharply (Human Rights Watch, 2002~. Violent acts included murder, physical assaults, arson, vandalism of places of worship and other property damage, death threats, and public harassment. Most of these incidents occurred between September 11, 2001, and December 2001. Ac- cording to Federal Bureau of Investigation (FBI, 2002) statistics, the num- ber of anti-Muslim hate crimes rose from 28 in 2000 to 481 in 2001. Similar increases in the numbers of anti-Muslim hate crimes have been reported in relation to the Oklahoma City bombing, the crash of TWA Flight #800, and the Persian Gulf War (Human Rights Watch, 2002~. In contrast, terrorism events, like other disaster events, can also pro- duce unique positive outcomes for the community. Because terrorism is generally directed at a population or subpopulation, there is often a sig- 7 Active coping strategies are behavioral or psychological responses intended to change the nature of the stressor itself or the way in which one thinks about it. Turning to others for support and attempting to gain more information about the stressor are examples of active coping strategies.
60 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM nificant growth of patriotism and pride for the population following the event. For example, after the terrorism events on September 11, 2001, many people reported an increased appreciation for the freedom afforded by living in the United States (Silver et al., 2002~. People also reported closer relationships with their family members subsequent to those at- tacks (Silver et al., 2002~. Chemical, Biological, Radiological, and Nuclear Terrorism Chemical, biological, radiological, and nuclear terrorism (CBRN) de- serves special mention, given the unique characteristics. Such threats are unfamiliar, usually undetectable while they are dangerous, and often per- ceived as particularly reprehensible and unfair. These qualities present additional psychological challenges. The presence of an "incubation pe- riod" in which an individual may have been exposed to an agent but may not know the outcome is another unique and potentially stressful aspect of CBRN terrorism. In the case of a bombing or other physical terrorist attack, the individual will know immediately whether or not he or she has been physically harmed. A particularly difficult challenge that may present in cases of CBRN terrorism is the differentiation of apparent anxiety in people due to the possibility of exposure to a chemical or biological agent from direct neu- ropsychological or behavioral changes due to exposure to the agent. The initial presentation of a chemical and biological weapon attack may be neuropsychological symptoms. For example, acute poisoning with a sub- lethal dose of an organic phosphorus compound (e.g., sarin) produces cognitive impairments characterized by confusion, difficulty in concen- tration, and drowsiness (Jones, 1995~; individuals exposed to cyanide may initially present with anxiety and agitation, reflecting tissue hypoxia (Baskin and Rockwood, 2002~; and exposure to fungal toxins can result in psychosis, somatic complaints, anxiety, agitation, and involuntary move- ments (Benedek et al., in press). Furthermore, physical manifestations of panic such as shortness of breath might be mistaken as symptoms of in- fection or contamination, which then becomes a self-reinforcing cycle as the individual's panic is increased by the shortness of breath, resulting in an exacerbation of this symptom. Individuals with nonspecific somatic complaints such as nausea or weakness will be a great concern in the event of biological or chemical attacks when the presenting symptoms of exposure may be nonspecific and similar to other common conditions. For example, during the an- thrax attacks in fall of 2001, the initial symptoms of infection mimicked viral syndrome and influenza-like symptoms. Many emergency physi- cians and primary care physicians were overwhelmed with individuals
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 61 concerned about their exposure and requesting testing and/or treatment for anthrax exposure, which may or may not have occurred and for which tests were not always available. The extensive publicity about the an- thrax threat likely increased self-monitoring for symptoms. This scenario was also seen among the Israeli civilian population during the Gulf War when people went to hospitals concerned that they had been exposed to nerve gas from Iraqi Scud missiles (Golan et al., 1992~. The 1995 terrorist attack involving the nerve agent satin in the Tokyo subway system also illustrated this phenomenon. Almost 75 percent of those who went to the hospital and were reported as "injured" showed no effects of exposure to satin (Lillibridge et al., 1995~. An investigation conducted by Ohbu and colleagues (1997) examined various psychological distress responses in survivors of the satin gas attack. The individuals reported symptoms such as fear of subways (32 percent), sleep disturbances (29 percent), flash- backs (16 percent), and irritability (10 percent). RESEARCH CHALLENGES AND NEEDS Conducting research on the psychological consequences of terrorism and testing interventions in this setting are extraordinarily difficult given the chaos, unpredictability, and other complexities of major disasters. Consequently, studies often have to proceed in the absence of rigorous research methodologies, producing results whose validity may be ques- tionable, unreliable, and not applicable to the disaster setting or popula- tion of interest. Furthermore, the length of time typically needed for the approval and dissemination of funding may make it difficult to initiate research soon after a disaster occurs, which then results in findings that do not reflect the full time-course of response and recovery. The need to meet requirements of institutional review boards and other regulatory agencies also contributes to the time needed before commencement of research. Barriers such as these ultimately result in gaps in critical knowl- edge needed to direct interventions in settings of terrorism. The model depicted in Tables 1-3, 1-5, and 1-6 is a potentially compre- hensive structure for directing future research, and providing a frame- work for research to recognize and address the gaps. Much has yet to be learned even on the basic epidemiologic level, such as the incidence of psychiatric illnesses in various disaster populations when comparing ter- rorism with other kinds of events. Researchers use various instruments to measure many different variables so that comparison between studies is difficult if not impossible. Intervention studies are exponentially more difficult to conduct than epidemiologic research because of both the need to enter the field quickly before other interventions have contaminated the course of recovery in the population and the need to apply standard
62 PREPARING FOR THE PSYCHOLOGICAL CONSEQUENCES OF TERRORISM methods of treatment evaluation such as randomized, double-blind, pla- cebo-controlled studies. Therefore, even less is known about the effec- tiveness of interventions for traumatic stress following disasters and ter- rorism. The field has resorted to applying interventions developed for other populations that are untested in disaster settings, some of which may be unhelpful or possibly even harmful. Even more complex than epidemiologic and treatment effectiveness research in disaster settings are studies of community systems of response to disasters and terrorism. Throughout this chapter, we have highlighted areas where additional and more rigorous research is necessary. These areas include the psycho- logical consequences and response implications of hoaxes and false alarms, and of attacks with conventional explosives or a CBRN weapon such as the release of a highly infectious disease. In addition, research that refines possible population-based predictors of adverse outcomes af- ter terrorism events, including ethnicity, age, and other pre-existing char- acteristics, is needed to guide future outreach and intervention efforts. Evidence is lacking on substance abuse outcomes after a terrorism event, and on interventions for these behaviors. The role of media images in spreading terror remains unclear, and should be examined as well, so that potentially adverse psychological consequences can be minimized. Fi- nally, the identification of factors that may influence community and in- dividual resilience is required in order to inform future interventions. As noted throughout this chapter, a lack of indicators of the population's psychological health prior to terrorism events limits the conclusions that can be drawn from research conducted after events. Ongoing surveil- lance will be of benefit in determining the psychological consequences of events and effectiveness of specific interventions. SUMMARY The trauma and disaster literature provides some indication of how individuals and communities may react to terrorism events. Research examining the psychological consequences of terrorism, although in its infancy, indicates that psychological difficulties will certainly result for many. Most of those with psychological consequences will present with mild distress symptoms and behavioral changes, while only a few may present with severe symptoms that meet the criteria for psychiatric ill- ness. The malicious intent and unpredictable nature of terrorism may carry a particularly devastating impact for those directly and indirectly affected. However, despite the devastating nature of terrorism, commu- nity cohesion and posttraumatic growth are possible. Although psychological effects of terrorism are virtually certain, rela- tively little is known about particular consequences for various subgroups
UNDERSTANDING THE PSYCHOLOGICAL CONSEQUENCES 63 of the population or how people may react to different types of events. There is some evidence that children, survivors of past traumatic events (including refugees), ethnic minority populations, and those with preex- isting psychiatric illness may be especially vulnerable to psychological consequences, although some of these data are contradictory. Events of closer proximity, longer duration, and greater intensity might be expected to result in increased psychological consequences. The broader trauma literature may begin to help direct prevention and intervention efforts in response to terrorism events. However, it is no longer sufficient to rely on information obtained from research on other kinds of traumatic events because disasters, and particularly terrorism, differ in fundamental ways. Continued research examining the psycho- logical consequences from a range of disaster and traumatic events will help improve understanding of the impact and provide evidence to target interventions. Finding 2: Terrorism and the threat of terrorism will have psycho- logical consequences for a major portion of the population, not merely a small minority. Research studies that have examined a range of terrorism events indicate that psychological reactions and psychiatric symptoms clearly develop in many individuals. To op- timize the overall health and well being of the population, and to improve the overall response to terrorism events, it is necessary that these potential consequences be addressed preventively as well as throughout the phases of an event.