Following the terrorist attacks of September 11, 2001 in New York City, I undertook a series of epidemiological studies, funded in large part by the US Centers for Disease Control and Prevention, to describe population health effects in New York.

In this meta-analysis, I attempted to synthesize what is known about the behavioral health effects of terrorism. The United States Department of State has documented 228 acts of worldwide terrorism between 1961 and 2003. Of these 197 were in the developing world. In the US, attention has turned to the threat of terrorism with the September 11, 2001 terrorist bombings, the largest single-day loss of human-life in US history since the Civil War. Subsequent terrorist attacks such as the October 12, 2002 Bali nightclub bombings, the March 11, 2004 Madrid train bombings, and the July 7, 2005 London bombings, have further brought the threat of terrorism to the forefront of national and international discourse. Several large-scale reviews of the consequences of disasters have been published. These reviews have documented the prevalence and correlates of specific psychiatric disorders and behaviors after mass events. Post-traumatic stress disorder (PTSD) emerges from this work as the best studied, and likely most common, psychopathology after disasters. One theme to arise from these reviews is that disasters that are caused by human-intent (such as terrorism) may be associated with a particularly high risk of psychopathology in their aftermath. To illuminate this issue, we undertook a review and synthesis of quantitative studies of the behavioral health effects of terrorist incidents focusing primarily on the prevalence and correlates of PTSD.

In this textbook chapter we reviewed the available evidence about the mental health and behavioral consequences of terrorism, considered methodological and research issues that challenge the field, and discussed the evidence for specific prevention and treatment efforts aimed at mitigating the mental health and behavioral consequences of terrorism. In this more recent textbook chapter, we focussed on the events of September 11, 2001 in New York City.

In this review article we focused on the clinical implications of terrorist-related behavioral health disorders. Emergency physicians are likely to be first-line responders in any local or regional terrorist event. In addition to preparing for the potential physical conditions and injuries that are associated with terrorism, they should be aware of the behavioral and mental health implications as well. It is helpful to be familiar with the characteristics that predict who may be at increased risk for mental illness after such events and how they may be identified in an Emergency Department setting. Although most people in the general population with behavioral conditions stemming from a terrorist event can be expected to recover spontaneously within several months, other individuals are at increased risk of developing more debilitating mental health conditions that have been associated with post-terrorist and disaster environments. Screening tools are available to help emergency practitioners identify them and refer patients for more formal psychiatric evaluation and potential interventions to facilitate and speed the recovery process.

After writing up some initial reviews, we conducted a series of more analytic studies.

To illustrate how spatial modeling methods may provide insight about the relation between proximity to mass trauma and substance use, we examined the role of proximity to a terrorist event in determining risk of substance use-related diagnoses. Previous analyses that have assessed changes in substance use following mass traumas such as terrorist attacks have produced conflicting results. We used Bayesian hierarchical modeling methods to assess whether distance from the World Trade Center (WTC) site in the aftermath of the September 11, 2001 terrorist attacks was associated with risk of substance use-related diagnoses. In analyses controlling for age, gender, median household income and employment-related exposure to the terrorist attacks, we found that each two mile increment in distance away from the World Trade Center site was associated with 18% more substance use-related diagnoses in the population we studied; this relation between distance from the WTC and substance use-related disorder was the opposite of the relations observed one year before the same attacks in the same area. By accounting for spatial relationships that may influence the population risk of substance use health disorder, this approach helps explain some of the conflicting observations in the extant literature. These methods hold promise for the characterization of disease risk where spatial patterning of exposures and outcomes may matter.

While several population-based studies documented behavioral health disturbances following terrorist attacks, a number of mental health service utilization analyses presented conflicting conclusions. We tried to determine if mental health service utilization increased following a terrorist attack by assessing changes in psychoactive drug prescription rates. We measured the rate of selective serotonin reuptake inhibitor (SSRI) prescriptions among New York State Medicaid enrollees before and after the terrorist attacks of September 11, 2001, and assessed the association between geographic proximity to the events and changes in the rate of SSRI prescriptions around September 11, 2001 We found that from September to December 2001, among individuals residing within 3 miles of the WTC site, there was an 18.2% increase in the SSRI prescription rate compared to the previous 8 month period (p=0.0011). While there was a 9.3% increase for non-New York City residents, this change was not statistically significant (p=0.74). We concluded that there was a quantifiable increase in the dispensing of psychoactive drugs following the terrorist attacks of September 11, 2001 and that this effect varied in response to geographic proximity to the events. These findings build on the growing body of knowledge on the pervasive effects of disasters and terrorist events for population health and demonstrate the need to include mental and behavioral health as key components of surge capacity and public health response to mass traumas. We presented a shorter version of this material here.

We also looked at population-level psychiatric disturbances spatially. We wanted to assess the appropriateness of using Bayesian hierarchical spatial techniques to answer the question of the role of proximity to a mass trauma as a risk factor for psychopathology. Using a set of individual-level Medicaid data for New York State, and controlling for age, gender, median household income and employment-related exposures, we applied Bayesian hierarchical modeling methods for spatially aggregated data. We found that distance from the World Trade Center site in the post-attack time period was associated with increased risk of anxiety-related diagnoses. In the months following the attack, each 2-mile increment in distance closer to the World Trade Center site was associated with a 7% increase in anxiety-related diagnoses in the population. No similar association was found during a similar time period in the year prior to the attack. We conclude that spatial variables help more fully describe post-terrorism psychiatric risk and may help explain discrepancies in the existing literature about these attacks. These methods hold promise for the characterization of disease risk where spatial patterning of ecologic-level exposures and outcomes merits consideration.

We looked closely at the role of emergency departments in providing behavioral and psychiatric health care following the terrorist attacks of September 11, 2001. We assessed presentations to emergency departments using Medicaid analytic extract files for adult New York State residents for 2000 and 2001. We created four mutually exclusive geographic areas that were progressively more distant from the World Trade Center and divided data into 4 time periods. All persons in the files were categorized by their zip code of residence. We coded primary emergency department diagnoses for post traumatic stress disorder, substance abuse, psychogenic illness, severe psychiatric illness, depression, sleep disorders, eating disorders, stress-related disorders, and adjustment disorders. There was a 10.1% relative temporal increase in the rate of emergency department behavioral and mental health diagnoses following the September 11, 2001 terrorist attacks for adult Medicaid enrollees residing within a 3-mile radius of the World Trade Center site. Other geographic areas experienced relative declines. In population-based comparisons, Medicaid recipients, who lived within 3 miles of the World Trade Center following the September 11, 2001 terrorist attacks had a 20% increased risk of an emergency department mental health diagnosis (Prevalence Density Ratio 1.2, 95% CI 1.1, 1.3) compared to those who were non-New York City residents. The complex role that emergency departments may play in responding to terrorism and disasters is becoming increasingly apparent. To the best of our knowledge this is the first report of a quantifiable increase in emergency department utilization for mental health services by persons exposed to a terrorist attack in the United States.

Finally, we looked at how academic institutions and public health agencies can partner to prepare for and respond to terrorism and disasters. The New York City Department of Health and Mental Hygiene and the Columbia University Mailman School of Public Health's National Center for Disaster Preparedness undertook a collaborative project to establish a model academic health department. The goals were to increase student participation at the health department, increase faculty participation in health department activities, and facilitate health department faculty appointments at the school. As a result, 17 students were placed in full-time summer research projects designed by health department staff specifically for the project, 154 health department staff attended a series of six lectures presented by faculty, and five health department professionals applied for academic appointments at the school. The benefits of the efforts toward establishing an academic health department extend to all areas of public health practice, including those of preparedness.