Lacking systematic research on mental health effects of bioterrorism to guide them, authorities were not sufficiently prepared to respond to the anthrax attacks in the weeks following the September 11, 2001, terrorist attacks. Complementary findings from systematic observations on survivors of anthrax infection in previous research1
together with the current study of a broader exposure group constitute a new empirically based literature on mental health effects of bioterrorism. This work may inform responses to future incidents including not only bioterrorist attacks but also chemical or radiological accidents, emerging infectious diseases, and pandemics such as the severe acute respiratory syndrome (SARS) outbreak and the more recent 2009 H1N1 epidemic.38
All of these events are associated with fear and uncertainty about exposure and/or contagion and raise public health concerns. In mass emergencies involving large populations with uncertain exposures, small fractions of the populace becoming convinced they were exposed and rushing to seek medical care could translate into massive numbers of patients overwhelming the surge capacity of acute care systems.10,39
Extrapolating the proportions of people in this limited study who incorrectly believed they had been personally exposed in order to anticipate in future disasters the raw numbers of people who believe they have been exposed indicates a potentially important public health consequence, if people alter their healthcare behavior based on misunderstanding. In this Capitol Hill anthrax attack study, a sizeable proportion of those unexposed, especially men, believed they had been exposed. To our knowledge the finding that, among those who were not exposed, men were more likely than women to believe that they had been exposed has not been previously reported. This result is not consistent with previous studies that demonstrate greater perception of threat and threat-related anxiety among female exposure groups compared to males,40,41
with the well-known preponderance of PTSD among female trauma-exposure groups,42
or with general symptom-reporting patterns among women compared to men.43
The false belief in exposure among men in this sample could well represent a false-positive artifact of this particular dataset, or it could reflect unique psychological characteristics of the men and women who work for Congress.
Even though no congressional workers became ill with anthrax infection, many had symptoms that they suspected represented anthrax infection and they sought medical care. Among those in this study who were not exposed, belief in exposure was also associated with emotional upset, concern about mortality, and taking antibiotics (despite being told antibiotics were not needed for their exposure category). Therefore, those who incorrectly believe they were exposed may warrant attention and potential interventions as well as those actually exposed, although reaching them may be complicated by loss of trust in authorities.
Despite the risk of contracting a serious, potentially fatal disease from anthrax, antibiotic adherence was far from perfect. Fewer than half of those who were prescribed antibiotic prophylaxis completed the entire antibiotic course (most often stopping it due to side effects), and only one-fourth took their antibiotics flawlessly. The incidence of side effects for the ≥60-day regimens observed here differed from typically brief (≤10-day) courses of these commonly used antibiotics for ordinary infections in community settings; joint and tendon problems constituted the biggest side effect, along with gastrointestinal side effects.
The treatment adherence findings of this study parallel research reported by the Centers for Disease Control and Prevention (CDC) that just over one-half of congressional workers completed their 60-day course of antibiotics.4
Gulf War veterans participating in a 6-month doxycycline prophylaxis study also exhibited problems with side effects and poor medication adherence.44
Adherence to protracted antibiotic regimens for individuals who feel healthy might be expected to be less than for short-term acute antibiotic treatment of infectious illness45-47
and more similar to long-term medication for chronic diseases such as tuberculosis, hypertension, or diabetes.48,49
Providers of extended prophylaxis following bioterrorism or other mass exposures may thus anticipate the discontinuation of antibiotics and other antidotes with treatment courses of 2 months or longer, potentially leading to negative medical outcomes.
The sample for the current study represented a relatively young and educated group with an almost ideal access to medical care and public health authorities. Unlike the thousands of postal employees who were potentially exposed during the same period, congressional staff (especially those known to be highly exposed) had numerous onsite physicians, ready access to authorities from the military and CDC, and nearly daily briefings from healthcare providers regarding anthrax; questions regarding their individual symptoms or concerns were addressed by physicians within hours. It is likely that the abundant personal communication of medical information from Capitol Hill physicians to staff reduced distress and inappropriate responses, which otherwise might have been far worse.
Yet, despite this level of access and their high educational level, the staff's unfounded fears and nonadherence with prophylaxis were quite prevalent. Such responses might be anticipated to be even more evident in general populations without these advantages. The Hart and Brentwood postal employees, who were not afforded this level of targeted risk communication, demonstrated greater mistrust of health authorities, although trust issues also may have sorted across racial lines among the predominantly African-American postal employees.27-30
In a mass exposure event, such as an aerosol exposure over a city or a packed sports stadium, it would be impossible to provide the level of personal contact with all exposed individuals that the Capitol Hill staff was afforded. This further suggests a considerable challenge for public health authorities in any future bioterrorism event, especially one on a large scale.
The causal pathways of the associations with belief in exposure found in this study are not certain. Possibly, because people believed they were exposed they became more upset, thought they might die, and sought out antibiotics. Alternatively, being upset or receiving antibiotics might have contributed to their belief that they had been exposed, or other factors associated with belief in exposure, being upset, and receiving antibiotics may indirectly link these findings. To the degree that belief in exposure generates emotional distress and seeking of unnecessary treatment, targeted risk communication to help align exposure beliefs with actual exposure status could reduce levels of emotional distress and unnecessary healthcare use. If, however, belief in exposure is generated by individuals' interpretation of healthcare measures (“I was prescribed antibiotics—that must mean I was exposed”), then risk communication can be targeted to better inform people of the significance of medical treatments in order to reduce erroneous conclusions about personal exposure. Clarification of the mechanisms of these associations may help direct future public health and occupational interventions: screening, public education about what constitutes exposure and worrisome symptoms, reassurance, and workplace preparation for these types of disasters.
Psychopathology in these congressional workers after the anthrax attacks was associated with exposure. Among the most highly exposed individuals (those with positive nasal swab tests), rates of psychiatric disorders (anthrax-related PTSD in 27%, any postdisaster disorder in 55%) were not unlike those identified in directly exposed survivors of the Oklahoma City bombing (PTSD in 34%, any disorder in 45%).37
This is somewhat surprising given the absence of violence and abject horror in the exposure experiences of these anthrax victims compared to the survivors of the Oklahoma City bombing. The invisible nature of the bioterrorism attack, however, as discussed earlier in this article, may have yielded less apparent psychological effects compared to the more evident response to the example of a terrorist attack using conventional weapons in the Oklahoma City bombing. Further contributors to psychological reactions to the anthrax attacks among Congressional staff may relate to the high-profile and national nature of the anthrax attacks as well as the fact that the anthrax attacks followed soon after the September 11 terrorist attacks (in which Capitol Hill was a target), almost blending the attacks in the perception of the public and of those directly exposed. Regardless, the amount of psychopathology found in the most directly exposed survivors of the anthrax attacks on Capitol Hill underscores the importance of addressing mental health service needs. Mental health assessment and treatment might best be delivered if integrated with the medical services for those actually exposed or infected.
Although psychological stress was prevalent, with 48% of the sample acknowledging a great deal of stress, the source of the stress was more often unrelated to terrorism or to circumstances indirectly related to terrorism than focused on exposure to terrorism. Thus, it should not be assumed, without inquiry, that mental health problems following terrorism are necessarily direct consequences of the incident.
Although inclusion of exposed and unexposed groups and systematic interviews with structured diagnostic assessment were strengths of this research, the sample may not be representative of the potentially exposed Capitol Hill population, given the 47% nonparticipation rate among those most highly exposed and the volunteer sampling. This sample may be overly inclusive of highly exposed people with an interest in discussing their experience yet lacking individuals who are so upset that they would avoid participation in a study reminding them of the incident and individuals unmotivated to participate because they feel they were little affected by the incident. The extreme tails of the normal curve—that is, those most and least upset—may thus be underrepresented. This population of young, educated, conscientious, motivated, and largely nonminority congressional workers may also be unrepresentative of other workplace populations. The postdisaster time window was relatively brief (several months); previous work, however, has shown that most disaster-related PTSD begins within a few months,37,50-53
allowing identification of cases in this study. Recall bias may have modified participants' retrospective recollection of predisaster and early postdisaster symptoms.
While some findings of the current study are specific to the population studied, others may represent more general responses to bioterrorism. Further research is needed with more representative populations to confirm the findings and determine generalizability. To the degree that the findings of this study are representative of other incidents and other populations exposed to bioterrorism, potentially important implications for public disaster health policy and intervention may follow. The possibility remains, however, that this could be a massively larger problem in a general population event in which the kind of personal intervention provided by public health authorities on Capitol Hill may not be feasible.
Despite methodological limitations of this study, the findings suggest important public health, mental health, and social implications. Mental health service needs associated with bioterrorism range from public education and outreach, commonly provided after disasters, to traditional services for those with psychiatric disorders. Confusion about health status requires clear communication for those needing treatment or prophylaxis and for the public at large. This communication must be delivered in an environment of diminished trust at a time when such trust is critically important to thwart an enemy, maintain public order, and focus social action. Thus, careful thought must be given to the content of messages, the modalities for disseminating messages, and the selection of credible spokespersons.
These research findings suggest that treatment adherence and trust in public health authorities represent areas of special concern in disasters involving biological, chemical, and radiological agents, warranting further study. A mental health research agenda for bioterrorism and related mass emergencies should be established to identify priorities to guide public health and mental health prevention and intervention strategies for these types of incidents.