Posttraumatic Stress Disorder Following the September 11, 2001, Terrorist Attacks: A Review of the Literature Among Highly Exposed Populations

Exposure to the trauma of disasters is common. A national survey in the United States suggested that more than 15% of women and 19% of men are exposed to disasters during their lifetime (Kessler, Sonnega, Bromet, Hughes, & Nelson, 1995). Although the consequences of disasters may include a wide range of psychopathology (Norris, Friedman, Watson, et al., 2002), in earlier community studies conducted prior to September 11, 2001, it had been shown that posttraumatic stress disorder (PTSD) is the most common type of psychopathology experienced in the aftermath of large-scale traumatic events (e.g., Breslau et al., 1998). The disorder involves substantial functional impairment and is often comorbid with other mental health conditions such as depression, generalized anxiety disorder, and substance abuse. For these reasons, PTSD is the most commonly studied mental disorder in the aftermath of disasters (for reviews, see Galea, Nandi, & Vlahov, 2005; Norris, Friedman, Watson, et al., 2002). Although PTSD symptoms have been documented for centuries, not until 1980 did the American Psychiatric Association officially add PTSD to the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM–III; American Psychiatric Association, 1980) nosologic classification system (Trimble, 1985). The DSM–III diagnostic criteria for PTSD were revised in DSM–III–R (American Psychiatric Association, 1987), DSM–IV (American Psychiatric Association, 1994), and DSM–IV–TR (American Psychiatric Association, 2000) and now include exposure to a catastrophic event involving death or injury or threat to one’s physical integrity (Criterion A1); a subjective response marked by intense fear, helplessness, or horror (Criterion A2); 17 symptoms in the three symptom clusters of intrusive recollections (Criterion B), avoidant and numbing symptoms (Criterion C), and hyper-arousal symptoms (Criterion D); duration of symptoms for at least one month (Criterion E); and functional limitation as a result of symptoms (Criterion F). Large-scale general population studies have supported the DSM–IV–TR notion that exposure to trauma precedes the formation of PTSD symptoms, and the estimated lifetime prevalence of PTSD among U.S. adults from these studies is documented at 8% (10% in women, 5% in men), with great variability depending on the type of trauma experienced (Kessler et al., 1995, 1999). Terrorist events by design are traumatic events that erode security and safety. In the last decade, such attacks have increased in sophistication and had enormous impact in terms of loss of life and damage (Bongar, 2006). The terrorist attacks on the World Trade Center (WTC) and the Pentagon on the morning of September 11, 2001 (9/11), have been life changing for many individuals (Neria, Gross, Marshall, & Susser, 2006). Immediately following the attacks, three national studies found widespread posttraumatic stress symptoms in the general U.S. population. Within the first week after 9/11, Schuster et al. (2001) conducted a national random digit-dial telephone survey of 560 adults and found that 44% of participants reported substantial stress reactions. One to two months after the attacks, Schlenger et al. (2002) conducted a Web-based study with a nationally representative sample of 2,273 adults and reported a 4.3% prevalence of PTSD that was significantly associated with both the number of hours of television coverage of 9/11 watched and the number of 9/11-related graphic events watched on television. These two studies were followed by a national longitudinal Web-based survey of 2,729 adults conducted by Silver, Holman, McIntosh, Poulin, and Gil-Rivas (2002), who examined demographics, health history, lifetime exposure to stressful events, 9/11 exposures, and coping strategies. In three waves conducted (a) 9–23 days after 9/11, (b) two months after the attacks, and (c) six months after the attacks, the researchers found that within the first month, 12% of individuals reported acute stress symptoms and 8.9% reported symptoms involving functional impairment. The researchers also found that the course of posttraumatic stress symptoms went from 17% at two months to 5.8% at six months postattack. Taken together, these studies presented initial evidence that the 9/11 attacks, whether proliferated by media images or by concerns about safety in times of war and terrorism, were significantly associated with PTSD symptoms in the general U.S. population. Whereas countless viewers in the United States and worldwide were exposed to the events of 9/11 indirectly, many individuals were highly exposed in the major metropolitan areas of New York City (NYC) and Washington, DC. In NYC alone, the destruction and damage to the WTC Twin Towers and 35 surrounding buildings resulted in almost 3,000 fatalities, 150,000 jobs lost, and $50 billion to $100 billion in economic costs (Bram, Orr, & Rapaport, 2002). After the attacks, the recovery and cleanup period was lengthy, lasting through June 2003. High exposure to the 9/11 attacks in NYC therefore encompassed a myriad of experiences dependent on such factors as one’s specific location on 9/11 (i.e., proximity to the WTC), place of residence (i.e., proximity to lower Manhattan), and participation in rescue and recovery efforts. Accordingly, several research groups have reported on 9/11-related PTSD among highly exposed groups. The objective of this review is to systematically assess the evidence about PTSD following high exposure to the 9/11 attacks and to identify the key challenges in the extant literature.