498 TREATMENT OF SPECIFIC ANXIETY DISORDERS
epiDemiology anD CliniCal featuresPrevalence of Trauma Exposure
A large discrepancy exists between the number of people exposed to traumatic events
that meet DSM-IV-TR Criterion A and the much smaller minority who eventually
develop PTSD. In fact by the beginning of adulthood 25% of individuals have experi-
enced at least one traumatic event and by age 45 the majority of adults will have experi-
enced trauma, with a significant number of individuals experiencing multiple traumatic
events (Norris & Slone, 2007). Of course prevalence rates of traumatic stress increase
dramatically in populations exposed to war, community violence, natural disasters, and
the like.
Analysis of the NCS data set indicated that 60.7% of men and 51.2% of women
experienced at least one DSM-III-R traumatic event, the most common being witness-
ing someone being badly injured or killed, being involved in a fire or natural disaster,
and being involved in a life- threatening accident (Kessler, Sonnega, Bromet, Hughes &
Nelson, 1995). Other large epidemiological or community studies have confirmed that
two- thirds to 90% of adults have experienced at least one traumatic event in their life-
time (e.g., Breslau et al., 1998; Creamer, Burgess, & McFarlane, 2001; Elliot, 1997).
The frequency and type of trauma exposure is not evenly distributed across the
population. Although it is not clear whether some ethnic groups experience more or less
trauma than others, it may be that inner-city residents are exposed to more community
violence (see Norris & Slone, 2007). Furthermore, certain occupations are associated
with higher rates of traumatic exposure such as military personnel, paramedics, urban
firefighters, and the like (e.g., Corneil, Beaton, Murphy, Johnson, & Pike, 1999; U.S.
Department of Veteran Affairs, 2003). Moreover, countries that are war-torn, politi-
cally unstable, or have low living standards have higher rates of trauma exposure in
their population (e.g., Sachs, Rosenfeld, Lhewa, Rasmussen, & Keller, 2008; Seedat,
Njenga, Vythilingum, & Stein, 2004; Turner, Bowie, Dunn, Shapo, & Yule, 2003).
Gender is another important factor in prevalence of trauma. Although men are
exposed to more traumatic events than women (e.g., Breslau et al., 1998; Vrana &
Lauterbach, 1994), women are more likely to experience interpersonal trauma such
as physical or sexual assault, rape, and child abuse and men more often report crimi-
nal victimization, fire/disasters, life- threatening accidents, combat, and being held cap-
tive (Breslau et al., 1998; Creamer, Burgess, & McFarlane, 2001; Kessler, Sonnega, et
al., 1995; Williams, Williams, et al., 2007). In fact approximately one-third of women
experience sexual or physical assault (Resnick, Kilpatrick, Dansky, Saunders, & Best,
1993). Physical and sexual assault are associated with the highest rates of PTSD, with
rape being particularly toxic for posttraumatic disorder (Norris, 1992; Resnick et al.,
1993). In a well-known study by Rothbaum, Foa, Riggs, Murdock, and Walsh (1992),
rape victims were prospectively assessed 9 months after the assault. At initial assessment
94% met symptom criteria for PTSD, at 1 month 65% met criteria, at 3 months 47%
had PTSD, and at 9 months 47.1% met PTSD diagnostic criteria. Thus, interpersonal
traumatic events involving a direct threat to an individual’s life or safety are associated
with the highest rates of PTSD. This trend is also seen in military samples in which there
is a significant relationship between amount of combat exposure and rates of PTSD
(e.g., Hoge, Auchterlonie, & Milliken, 2006).