Vol.2, No.4, 332-341 (2010) Health
Copyright © 2010 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
Social support and coping as moderators of perceived
disability and posttraumatic stress levels among
Vietnam theater veterans
Erin Martz*, Todd Bodner, Hanoch Livneh
Portland State University, Portland, USA; martzerin@gmail.com
Received 3 December 2009; revised 11 January 2010; accepted 15 January 2010.
The dual purpose of this study is to investigate
whether disability predicts posttraumatic stress
levels among Vietnam theater veterans, and
whether coping and/or social support moder-
ates the impact of disability on PTSD levels,
after controlling for demographic, pre-military,
military, and post-military factors. This research
analyzed data from the U.S.’s National Vietnam
Veterans Readjustment Study (NVVRS), which
was a nationally representative, stratified, ran-
dom sample of 3,016 Vietnam veterans. The re-
sults indicated that disability, emotional support,
instrumental support , and wishful thinking cop -
ing significantly predicted PTSD, when control-
ling for demographic, pre-military, military, and
post-military factors. Further, interactions indi-
cated that both emotional social support and
problem-solving coping significantly decreased
the impact of disability on PTSD levels. Implica-
tions of this research are briefly discussed.
Keywords: Disability; Social Support; PTSD;
Vietnam Veterans
An extensive amount of published research has exam-
ined psychiatric disorders, which may include posttrau-
matic stress disorder (PTSD), as sequelae of involve-
ment in wars [1-4]. While some research has focused on
the physical health consequences of exposure to extreme
stress [5,6], limited research has been conducted on the
psychological reactions occurring after the onset of an
injury or permanent disability in the context of war [7,8].
Moreover, there is a paucity of research on PTSD related
to disability that occurred specifically in a war-zone.
There has been increasing scientific interest on coping
with a disability [9]; yet, few studies have been conduc t e d
that examined coping with a war-related disability. To
date, research has not yet examined the possible moder-
ating effect of coping or social support on disability and
PTSD levels.
The need to conduct such research has been stated by
Kulka and colleagues, who concluded that “Vietnam
theater veterans with service-connected physical dis-
abilities are at elevated risk for a variety of readjustment
problems” [1], and more recently, by a 2006 working
group on deployment-related adjustment and mental
disorders [10]. The dual purpose of this study is to in-
vestigate whether disability predicts PTSD levels among
Vietnam theater veterans, and whether there are possible
moderators of this association, such as coping or social
support, after controlling for select demographic, pre-
military, military, and post-military related variables.
The following sections will review the extant literature
on: 1) PTSD and disability; 2) coping and PTSD; and 3)
the significant findings of research that examined PTSD
in analyses of the NVVRS dataset.
When evidence of a traumatic event remains present in
an individual’s life, such as in the form of an injury or
disability, it may serve as a visual or proprioceptive cue
to the trauma [11,12]. Thus, injury or disability may act
as a continuous reminder that can trigger anxiety for
certain individuals. Research has indicated an associa-
tion between PTSD and the existence of injuries, medi-
cal conditions, or disabilities [13-18], and that individu-
als may be susceptible to PTSD after an injury or the
onset of a disability [11,14,16,17,19-23].
In research conducted among veterans, Helzer, Robins,
and McEvoy [24] examined PTSD rates in a stratified
sample among 2,493 individuals, 64 of whom were
Vietnam veterans and 43 had experienced combat. Those
who experienced combat but were not wounded had a
4% rate of PTSD, compared to 20% rate among those
who were wounded. In a comparative study, Buydens-
E. Martz et al. / Health 2 (2010) 332-341
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Branchey, Noumair, and Branchey [25] found that vet-
erans with a combat injury had significantly higher
PTSD levels compared to veterans without injuries.
Martz and Cook [26] found the following rates of
PTSD among 45,320 veterans: burns 13.4%, spinal cord
injuries 11.6%, amputations 8.1%, major chest trauma
7.6%, heart failure/shock 7.3%, and cardiac arrest 5.1%.
They found that burns, spinal cord injuries, amputations,
and heart failure/shock were significant risk factors for
PTSD. Delimar and Sivik [27] assessed for PTSD in
three groups of so ldiers (N = 30 per group ), all of whom
had at least three months of combat experience in the
Croatian war of 1991-1993, and found a PTSD rate of
33.3% among soldiers with permanent disabilities (e.g.,
amputation). Among 312 veterans and civilians with
spinal cord injuries, Martz [28] found that total PTSD
levels were significantly predicted by spiritual/religious
coping, pain level, severity of SCI, and number of trau-
matic events.
The topic of PTSD reactions after the presence of a
disability among veterans is important for several rea-
sons. Kaplan, Huguet, McFarland, and Newsom [29]
found that male veterans who had activity limitations
(i.e., a disability) were significantly more likely to com-
mit suicide than non-veterans without disabilities. Fur-
ther, the topic of war-related physical disability as a po-
tential trigger for PTSD reactions is imperative to study,
in view of the concept of “double PTSD” [13], which in
the present context can mean that the trauma of disabil-
ity interacts with the trauma of war. Disability may also
be a “crossover” trauma, which Terr [30] described as a
one-time event with long-term, continuous consequences
that may elicit a complex set of traumatic reactions.
Kulka et al. [1] analyzed data from the U.S.’s Na-
tional Vietnam Veterans Readjustment Study (NVVRS),
which was an epidemiological study of a nationally
representative sample of Vietnam veterans. One part of
their extensive analysis examined issues related to
Vietnam veterans’ physical health problems in relation
to PTSD versus no PTSD (see Exhibit VIII-2, contrast
C, in [1 ]). The result s indicated th at for both ma les and
femal es, in d ivid u als with P TSD rep or ted a s ign if ic ant ly
lower level of positive perceptions of current health
status and a significantly higher number of chronic
health problems than those without PTSD. In a differ-
ent section, Kulka et al. [1] reported that the group of
Vietnam veterans with a service-connected physical
disability (SCPD) was significantly more likely to have
current PTSD (21.4%) than the group of veterans
without a SCPD (14.5%) (current PTSD prevalence
indicates that the individual met the PTSD criteria
within 6 months of the assessment; lifetime PTSD
prevalence indicates that the individual met the criteria
for PTSD sometime in their life; see Reference [1]). To
put the disability and PTSD research in context, the
results of the NVRRS research on war-related PTSD
include the following. Kulka et al. [1] indicated that
15.2% of male combat veterans and 8.5% of female
combat veterans from the Vietnam war-theater met the
criteria for current PTSD prevalence. In contrast to the
NVVRS prevalence data, the current PTSD prevalence
found among Gulf War veterans were found to be 4%
of men and 9% of women at first assessment, increas-
ing to 11% of men and 21% of women at second as-
sessment 2 years later [31]. The aforementioned current
PTSD prevalence rates and the two findings related to
health factors, disability, and PTSD suggest that the
traumatic experience of incurring a disability is an is-
sue that deserves more careful investigation and greater
clarification of the associations, such as examining the
possible predictors of PTSD levels among veterans and
the possible mod erato rs of thes e associ ations .
The present research is distinct from three studies that
were published using the NVVRS database. First, in
contrast to Zatzick and colleagues’ [6] research that ex-
amined PTSD and health outcomes and functioning, the
present study incorporates a measure indicating an exis-
tence of a disability, in addition to also examining mod-
erators of PTSD. Second, whereas Suvak, Vogt, Savarese ,
King, and King [32] researched coping as a predictor of
adjustment (moderated by war-zone stress) without ex-
amining disability issues, the presen t study posits coping
as a moderator between disability and PTSD. Third,
while Martz, Bodner, and Livneh [33] examined coping
as a moderator of disability and adaptation, the current
study will investigate a different outcome—that of
PTSD—and whether both coping and social support are
moderators of disability and PTSD.
Regarding PTSD and coping research, a variety of asso-
ciations have been found among various types of coping
and PTSD [34-37]. Koenen, Stellman, and Stellman [38],
in a follow-up study of 1,377 American legionnaires
who served in Southeast Asia, concluded from their
findings that perceived social support is a significant
predictor of recovery from PTSD. One study examined
coping and PTSD in the context of disability: Lawrence
and Fauerbach [39] found that both avoidant and active
coping were positively and significantly associated with
PTSD at hospitalization and at 1-month follow-up
among 158 individuals with burn injuries.
Using the NVVRS dataset, Suvak et al. [32] exam-
ined whether war-zone coping strategies predicted life
adjustment, as measured by achievement, life satisfac-
tion, and lifetime adaptation, and as moderated by
combat exposure. Their study is mentioned because of
its use of coping strategies, which were grouped into 3
factors called problem-focused coping (PFC), emo-
E. Martz et al. / Health 2 (2010) 332-341
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tion-focused wishful thinking (EFCWT), and emo-
tion-focused blunting and venting (EFCBV). One find-
ing that is relevant to the present study is that Suvak
and colleagues noted that in the final step of their re-
gression analysis, non-linear (i.e., quadratic) associa-
tions were found among PFC and achievement, PFC
and lifetime adaptation, and EFCWT and achievement,
each varying as a function of combat exposure. This
research indicated that the use of emotional coping
strategies during combat predicted lowered life-ad-
justment after the war experience, which Suvak and
colleagues interpreted the non-linear associations as
suggesting that certain coping strategies are no longer
useful in increasingly stressful combat situations.
The research on coping with a disability has been
expanding at a rapid rate [40-44], (for a summary, see
[9]). The role of coping strategies following traumatic
brain injury (TBI) was investigated by Moore and
Stambrook [43,44]. In their earlier study of 53 male
survivors of TBI, individuals characterized by having 1)
higher use of positive reappraisal and self-controlling
coping strategies (as measured by the Ways of Cop-
ing-Revised Questionnaire; WOC-R), and 2) lower
external locus of control, reported significantly lower
mood disturbance and lower levels of depression. In the
authors’ latter study of 175 survivors of TBI, they re-
ported that coping strategies that included denial, es-
cape, and resignation were linked to poorer qual-
ity-of-life outcomes. The authors also suggested that
positive reappraisal appeared to be associated with
better psychosocial outcomes.
Social support, which can be defined as “the perception
of the value of social interactions” [45], should be dis-
tinguished from the concept of a “social network,”
which refer to the quantity of relationships that a per-
son has. Lazarus and Folkman [45] further elaborated
on the definition of social support as “a resource,
available in the social environment, but which the per-
son must cultivate and use” [45]. They also noted that
while social support is typically deemed as a positive
resource and a buffer to stress, it also may have nega-
tive effects on people (e.g., it may create problems or
stress, provide misleading information, or create de-
pendency issues).
Thoits [46] suggested that social support could be
viewed as a form of coping assistance or support strategy.
Livneh and Martz [9] noted that social support can be
viewed as an “extra-individual” influence on coping pro-
cesses, like other environmental factors. Hence, social
support can be distinguished from a form of emotional
coping called “seeking social support” by the former
representing social support that is received and experi-
enced, versus the latter as actions taken to obtain social
The following NVVRS research indicated variables that
should be controlled for in the present study. Fontana
and Rosenheck’s [47] research examined predictors of
PTSD by using structural equation modeling (SEM)
among a male sub-sample from the NVVRS data. One
demographic predictor (ethnicity), 2 military-related
variables (exposure to combat and participation in abu-
sive violence), and 2 post-military traumas (rejection by
society at homecoming, and lack of support by family
and friends) directly predicted PTSD. In a later study
using NVVRS data, Fontana and Rosenheck [48] fo-
cused only on war-zone stressors among male veterans.
Their SEM analysis indicated that only 2 variables had
direct, significant effects on PTSD: insufficiency of re-
sources in the environment and killing of others.
King and colleagues published 3 different analyses
using the NVVRS dataset. Using SEM, King, King,
Gudanowski, and Vreven’s [49] research, which focused
only on war-zone stressors, indicated that the following
war-zone stressors significantly predicted PTSD: per-
ceived threat, malevolent environment, and atrocities/
abusive violence. King, King, Foy, and Gudanowski [50]
examination of pre-war factors and war-zone stressors
found that for male and female theater veterans, prior
trauma history, age (for men only), atrocities/abusive
violence, malevolent environment, and perceived threat
had significant direct effects on PTSD. King, King, Foy,
Keane, and Fairbank’s [51] NVVRS research indicated
that the following predicted PTSD: early trauma history
(women and men) and age at entry into Vietnam (men),
atrocities-abusive violence and perceived threat (for both
men and women) and malevolent environment (for men),
additional stressful life events, hardiness, and functional
social support (for men and women) and structural social
support (for men).
The purpose of this research is two-fold: to investigate,
after controlling for demographic, pre-military, military,
and post-military factors, whether 1) disability predicts
PTSD levels in Vietnam theater veterans, and 2) coping
and/or social support moderates the impact of disability
on PTSD levels. Based on the literature about coping, it
is hypothesized that emotion-focused coping is posi-
tively related to PTSD levels, while social support, so-
cial coping, and problem-solving coping are inversely
related to PTSD levels.
E. Martz et al. / Health 2 (2010) 332-341
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7.1. Participants
The data were obtained from the National Vietnam Vet-
erans Readjustment Study (NVVRS), a nationally repre-
sentative, stratified, random sample of 3,016 Vietnam
veterans drawn from 8.2 million veterans who were on
active duty during the Vietnam war and who had left U.S.
military service by September, 1987 [52]. The data were
collected by means of extended interviews and self-re-
port questionnaires between 1986 and 1988 [1,2]. Sev-
eral groups were intentionally over-sampled in this study:
African Americans, Hispanics, women, and veterans
with service-connected disabilities [49]. Refer to Kulka
et al. [1,2] for an extensive summary of demographic
characteristics of this sample. In the current study, we
limited our attentio n to the 1618 theater veterans, that is,
only those who served within the war theater.
For this study, all the NVVRS data were used in factor
analyses of the variables. For the examination of the
research questions, the data from the Vietnam theater
veterans (n = 1618) were used, due the large amounts of
missing data for the variables considered among other
participants (e.g., non-theater veterans, civilians) in the
NVRRS dataset.
7.2. Instruments
7.2.1. PTSD
In the NVVRS, a multi-method approach was used to
assess PTSD with 3 primary and 7 secondary indicators
of PTSD [1]. For this research, the Mississippi Scale for
Combat Related Posttraumatic Stress Disorder (M-PTSD)
was selected because it has been used extensively for
measuring PTSD.The M-PTSD is a 35-item scale by
Keane, Caddell, and Taylor [53] that measures posttrau-
matic stress in military situations with higher scores in-
dicating greater likelihood of PTSD. Weiss et al. [52]
reported on the predictive validity of the various PTSD
scales used in the NVVRS; when comparing the survey
data with clinicians’ assessments, the M-PTSD achieved
a 77.3 sensitivity rate, 82.8 specificity rate, and a Kappa
of .53 for diagnosing PTSD.
7.2.2. Coping
In the NVVRS, 25 coping items were included, derived
from a large number of coping items from Folkman and
Lazarus’s [54] Ways of Coping Checklist [see 32 for
more details]. The original team of NVVRS researchers
selected these items as “most appropriate to coping with
the stressors of a war zone” [32]. The responses, after
reverse-coding, r epresented how much the veteran relied
on each way of coping (i.e., 1 = not at all to 5 = a great
deal). Prior research [33] on these items in the NVVRS
dataset has identified three distinguishable coping-
strategy dimensions: wishful-thinking coping (4 items;
= .78), social coping (2 items; = .67), and prob-
lem-solving cop ing (4 items; = .78). The social coping
factor included items about whether the respondent “de-
pended on o thers to cheer you up” and “saw someone to
help feel better.” Hence, social coping reflects strategies
that individuals use to handle stress, which in contrast to
the social support variable, refer to perceived external
support that is provided to individuals.
7.2.3. Instrumental and Emotional Social Support
To measure instrumental and emotional social support,
we used the 6-item Instrumental Social Support (= .75)
and 13-item Emotional Social Support ( = .77) scales,
respectively, which King et al. [49-51] formulated from
the NVVRS items and described in detail in their publi-
cations. Higher scale scores indicated greater levels of
each type of social support.
7.2.4. Disability
To assess disability, we used participan t responses to the
following question (item K4b in the NVVRS database):
“A military service-received wound handicapped me
later.” The response format was on a scale ranging from
1 “very true” to 4 “not at all true,” which was re-
verse-scored so that higher scores indicate stronger be-
lief that one had a service-related disability. This disabil-
ity item was selected from the available NVVRS item
pool because: a) it was a continuous, not categorical
variable; b) the question made a direct connection be-
tween injury incurred in the service and a disabling
status at a later time (i.e., a permanent disability, not a
temporary injury); and c) it was not a variable that rep-
resented financial compensation from the Veterans Ad-
ministration. Thus, the current research team deemed it
the best NVVRS item that represented d isability.
7.2.5. Demographic, Pre-milit ary, Military, and
Post-milit ary Risk Factors
Pre-military risk factors included gender (female = 1,
male = 0), ethnicity (1 = white, 0 = otherwise) [these two
variables, as categorical variables, were binary-coded for
the multiple regression], the number of traumatic events
experienced, and age at entry into Vietnam. Prior research
[49-51] measured the following four facets of mili-
tary-related stress in a war-zone: combat exposure (36
items), atrocities and abusive violence exposure (9 items),
perceived threat (9 items), and malevolent environment
(18 items). In our own analyses, we determined that many
of these scales were multidimensional and that many
items had large amounts of missing values. We therefore
created scales for these facets based on subsets of the
original itempool to improve the unidimensionality of the
scales and to minimize the amount of missing data. The
resulting scales had the following properties, with higher
scores indicating higher levels of each military-related
risk factor: combat exposure (12 items; = 92), atrocities
and abusive violence (3 items; = .76), perceived threat
E. Martz et al. / Health 2 (2010) 332-341
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(8 items;= .84), and malevolent environment (18
items; = .91). One post-military factor, the level of re-
adjustment problems (assessed by the NVVRS variable
“number of serious readjustment problems now”), was
included in this research. A list of the retained items for
the present study is avai lable from the authors on request,
whereas a list of the items used by King et al. [49-51] can
be obtained from those researchers.
7.2.6. Analysis Strategy
Because of the complex sampling methods used to gen-
erate the NVVRS data (i.e., stratified random sampling
with unequal sampling probabilities within strata), spe-
cial procedures must be used to estimate population pa-
rameter values (e.g., means, standard deviations, correla-
tions, and regression slopes). Therefore, we conducted
all analyses using the multilevel add-on package to the
M-plus 4.2 software program [55] that contains routines
for analyzing data from complex survey designs.
Building the regression model to test the study hy-
potheses consisted of a two-step process. In the first step,
a hierarchical linear regression analysis was conducted
where PTSD scores were regressed on predictor variables
that were entered in four successive blocks (see Results).
In the second step, a predictor selection process was used
to prune non-significant predictors of PTSD scores, start-
ing with the fourth block and working backwards. For
brevity, interpretations of the individual partial regression
slopes are presented only for the final regression model.
The statistical significance for the increase in R2 across
blocks is evaluated using 2 goodness-of-fit tests. The
statistical significance of individual regression slopes is
evaluated using Wald tests. To minimize collinearity
problems encountered when including interaction terms in
multiple regression models, variables involved in interac-
tions were centered around their estimated population
mean values prior to the construction of interaction terms
and subsequent analysis [56].
A moderation, instead of mediation, model was used
in this research, because coping was viewed as influenc-
ing the strength and direction of the associations among
pre-war, military, and post-military factors, disability,
and psychosocial outcomes. A mediation model would
have focused on whether these factors indirectly influ-
enced psychosocial outcomes through coping. Because
coping strategies are more of a fluid, state-like concept
[45,60,61] that is modifiable by th erapeutic interv entions ,
emphasis was placed in this study on examining coping,
and how coping altered the impact of the predictor vari-
ables on PTSD outcomes. The presence of significant
interactions indicates moderation by coping.
Throughout the analysis, =.05 was used to define sta-
tistical significance. Of the 1618 participants who served
in the Vietnam combat theater, 1443 provided complete
responses to all study variables. We conducted tests to
investigate mean differences for the studied variables
between the 1443 and 175 participants providing com-
plete and incomplete data, respectively. The results of
these tests suggest that the two participant group s did not
differ signif ican tly on mo s t of th e s tu d ied var ia b les ; ev en
in the case of significant differences, the variance in
these variables explained by respondent group was very
small (i.e., R2s = .008 and .009 for malevolent environ-
ment and perceived threat, respectively). Therefore, for
modeling convenience, the following analyses were
conducted only on those participants who provided
complete responses.
8.1. Descriptive Statistics
Table 1 provides the estimated population means and
standard deviations of the studied variables along with
the estimated population correlations among these vari-
Table 1. Estimated population means and standard deviations for and correlations among study variables.
Variable M SD 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1. PTSD Score 80.0 22.5 1.00 . . . . . . . . . . . . . .
2. Gender .002 .04 -.02 1.00 . . . . . . . . . . . . .
3. Ethnicity .86 .35 -.15 .02 1.00 . . . . . . . . . . . .
4. # of Traumas 3.47 2.89 .39 .01 .03 1.00. . . . . . . . . . .
5. Age at Entry 22.5 5.05 -.26 .04 .01 -.181.00. . . . . . . . . .
6. AA Violence .26 .36 .41 -.02 -.09 .26-.151.00. . . . . . . . .
7. Mal. Env. 2.80 .73 .53 -.01 -.18 .23-.21.471.00. . . . . . . .
8. Combat Exp. 2.11 .88 .44 -.04 -.12 .28-.14.67.601.00. . . . . . .
9. Perc. Threat 2.74 .76 .48 -.01 -.17 .27-. . . . . .
10. Readj. Probs. 1.46 .88 .56 -.01 -.13 .28-. . . . .
11. SR Disability 1.32 .77 .40 -.01 -.11 .21-. . . . .
12. Emot. Support 2.07 .46 -.61 .01 .09 -.28.19-.24-.38-.27-.29-.41-.23 1.00 . . .
13. Instr. Support .94 .17 -.44 .01 .05 -.12.00-.14-.18-.22-.19-.36-.17 .44 1.00 . .
14. WT Coping 3.14 .95 .46 -.01 -.15 .15-. -.26 -.11 1.00.
15. Social Coping 3. 71 .87 .27 .03 -.13 .15-. -.15 -.05 .511.00
16. PS Coping 3.02 .90 .14 .02 -.07 . -.14 -.17 .28.26
Notes: N = 1443; AA = Atrocities/Abusive, Mal. Env.= Malevolent Environment, SR = Service Related, WT = Wishful-Thinking, PS = Prob-
lem-Solving. All correlations > .01 in absolute values are significant at = .05
E. Martz et al. / Health 2 (2010) 332-341
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ables. Although the magnitude of the correlations be-
tween PTSD scores and the other study variables varied
considerably, all were statistically significant.
8.2. Hierarchical Regression Analysis
In order to investigate the two research questions, a hi-
erarchical regression analysis with interaction variables
was conducted. The ordering of the regression was based
on a temporal conceptualization of how the variables
might theoretical occur. The regression analysis ad-
dressed the first research question of whether, after con-
trolling for demographic, pre-military, military, and
post-military factors, disability predicts PTSD levels
among Vietnam theater veterans. The second research
question, of whether coping and/or social support mod-
erates the impact of disability on PTSD levels, was ex-
amined by the inclusion of interaction variables, which
represents moderation, in the regression eq uation.
The first bl oc k of predictor varia bles consist ed of vari-
ables prior research had identified as risk factors for
PTSD (i.e., gender, ethnicity, number of traumas, age at
entry to Vietnam war, combat exposure, atrocities /ab-
usive violence, malevolent environment, and perceived
threat during war, readjustment problems after service).
For the purpose of this investigation, these predictors
served as control variables and were not pruned in the
second model-selection step. These predictors account
for sizable and significant variance in PTSD scores, R2
= .53, 2 (9) = 479.86, p< .001.
The second block consisted of a single variable: ser-
vice-related disability. Including this variable led to a
significant increase in the variance explained in PTSD
scores, R2 = .02, 2 (1) = 13.65, p < .001, with a R2
= .55 after the second step.
Variables in the third block included two indicators of
social support [Emotional Support (ES), Instrumental
Support (IS)] and three coping styles [Wishful-Thinking
Coping (WTC), Social Coping (SC), Problem-Solving
Coping (PSC)]. These variables were added in block 3
based on the viewpoint that social support and coping
may act as a buffer between various stressors (block 1)
and the existence of a disability (block 2), and PTSD
(the outcome). Including these variables led to a signifi-
cant increase in the variance explained in PTSD scores,
R2 = .11, 2 (5) = 268.36, p< .001, resulting in a R2
= .66 after the third step.
The fourth and final block of variables tested modera-
tion of coping and social support. This block consisted
of interactions between service-related disability (SRD)
and the five variables in the third block (i.e., SRD x ES,
SRD x IS, SRD x WTC, SRD x SC, SRD x PSC). In-
cluding these variables led to a significant increase in the
variance explained in PTSD scores, R2 = .02, 2 (5) =
12.34, p = .03, resulting in a R2 = .68.
8.3. Pruning and Final Regression Model
As a result of the model-pruning process, three predic-
tor-variable interactions in block four (i.e., the interac-
tions between SRD and IS, WTC, and SC, SRD and SC)
and one predictor variable in block three (i.e., SC) were
dropped from the model. Dropping these four variables
did not result in a significant reduction in the variance of
PTSD scores explained by the model, R2 = .01, 2 (4) =
3.49, p = .48. The model R2 = .67 for the final model
indicated that the predictor variables explained approxi-
mately two-thirds of the variance in PTSD. Table 2 pr o-
vides the estimated regression partial regression slopes
for the final regression model. For brevity, we do not
interpret the slopes for the control variables (i.e., vari-
ables from Block 1) except to note that the valences of
these slopes are as expected based on past research.
Table 2. Final multiple regression model predicting PTSD scores.
Predictor Variable b SE (β)  
Gender –1.62 1.05 –.00
Ethnicity –1.57 1.40 –.02
Number of Traumas 0.84* 0.20 .11
Age at Entry Vietnam –0.25* 0.12 –.06
Atrocities/Abusive Violence 5.85* 1.83 .09
Malevolent Environment 1.16 1.23 .04
Combat Exposure 0.56 1.16 .02
Perceived Threat 3.35* 1.48 .11
Readjustment Problems 5.81* 0.65 .23
Service-Related Disability (SRD) 2.73* 0.84 .09
Emotional Social Support (ES) –12.88* 1.51 –.27
Instrumental S ocial Support –19.71* 3.79 –.15
Wishful-Thinking Coping 4.71* 0.67 .20
Problem-Solving Coping (PSC) –2.37* 0.65 –.10
SRD x ES Interaction –3.20* 1.41 –.07
SRD x PSC Interaction –1.53* 0.77 –.05
Notes: b re presents unstandardized regression slope esti mate with standard error SE (b); represents standardized regression slope
estimate. Significant slopes at α = .05 marked with an asterisk. N =1443. Model R2 = .67, 2 (16) = 756.81, p < .001.
E. Martz et al. / Health 2 (2010) 332-341
Copyright © 2010 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
Controlling for the other predictor variables in the
model, ES, IS, and PSC (at the mean of SRD) were
negatively and significantly related to PTSD scores and
WTC was positively and significantly related to PTSD
scores. Furthermore, controlling for the other variables
in the model, SRD was positively and significantly re-
lated to PTSD scores (at the mean of the ES and PSC
variables). However, the effect of SRD on PTSD scores
was qualified by significant interactions with ES and
PSC. In particular, the impact of SRD on PTSD scores
was smaller for both those with higher levels of ES and
higher levels of PSC.
The two-fold purpose of this study was to examine
whether perceived disability predicted PTSD levels and
whether coping and/or social support moderated the im-
pact of perceived disability on PTSD levels, after con-
trolling for demographic, pre-military, military, and
post-military factors. The results ind icated that p erceived
disability occurring during military service significantly
predicted PTSD, when controlling for other stressors,
such that more pronounced perceived disability is asso-
ciated with higher PTSD levels. Further, emotional so-
cial support (ES) was found to moderate between per-
ceived disability and PTSD, in dicating that the existen ce
of a disability had less of an influence on PTSD levels
among those with higher levels of ES. Problem-solving
coping (PSC) also moderated the association of per-
ceived disability and PTSD, such that a service-related
disability (SRD) had less influence on PTSD scores
for individuals with higher levels of problem-solving
That perceived disability was a significant predictor of
PTSD scores over and above other variables already
identified in the literature corresponds with what previ-
ous research has found in the general population [14-18]
and among veterans [25,26]. As discussed at the begin-
ning of this paper, Kulka and his colleagues [1,2] pre-
sented basic results regarding PTSD prevalence and
disability; the present research helps to refine this asso-
ciation by conducting a multivariate analysis that con-
trolled for multiple sources of stressors, and by examin-
ing coping interactions.
The direction of the significant zero-order correlation
between PTSD and emotion-focused, wishful-thinking
coping was in the hypothesized direction (r = .46, p
= .05), indicating that higher use of wishful-thinking
coping (WTC) was related to increased levels of PTSD.
Yet, the direction of the zero-order correlation between
PTSD and problem-solving coping was opposite (higher
use of problem-solving coping was related to increased
levels of PTSD) to what was hypothesized (r = .14, p
= .05). However, this zero-order relationship was re-
versed (r = -.10, p =.05), when examined through re-
gression analysis. Two possible explanations for this
phenomenon include: a) the operation of a minimal
amount of suppression, and/or b) the fact that after con-
trolling for all other confounding variables, the use of
problem-solving coping does act to attenuate the influ-
ence of disability on PTSD symptomatology, as origi-
nally hypothesized.
This study’s finding that problem-solving coping
moderates the association of perceived disability and
PTSD concurs with research on the role played by prob-
lem-solving coping in decreasing the impact of a range
of stressors. For example, Kennedy, Lowe, Grey, and
Short [57], in a sample of people with traumatic spinal
cord injuries, found a negative correlation between
problem-solving coping (active coping and planning)
and measures of depression, anxiety, and global psycho-
logical distress. Therapeutic interventions that integrate
problem-solving components (e.g., decision making,
time management, conflict resolution, money manage-
ment) could become useful in countering the impact of
functional impairments that are associated with d isability.
One example of such programs is Kennedy and Duff’s
program [62,63] for coping effectively with spinal cord
injuries. Problem-solving is a life-skill that can be used
for general problems, as well as for challenges directly
related to disability-related issues. Because the ex istence
of a disability often involves numerous challenges on
multiple levels (e.g., psychological, social, vocational,
environmental), therapeutic interventions to strengthen
problem-solving coping can help individuals better adapt
to their lives following the onset of disability.
The significant zero-order correlations between PTSD
and both emotional social support (r = -.6 1, p = .05) and
instrumental social support (r = -.44, p = .05) were in the
hypothesized directions, indicating that the use of social
support is inversely related to the presence of PTSD
symptoms, as hypothesized. Further, this study’s finding
of moderation by emotional social support—indicating
that the effect of disability on PTSD scores is smaller for
those with higher levels of emotional social support--is
also noteworthy. This corroborates with the earlier re-
ported findings [see 58] that the availability of social
support for people with disabilities bolsters one’s ability
to cope adaptively with life’s crises. The finding that
emotional social support statistically decreases the im-
pact of disability on PTSD lev els suggests that therapeu-
tic interventions that include interpersonal components,
such as family and group counseling, can help facilitate
the individual with a disability’s functioning and adapta-
tion to the onset of a chronic medical condition. There is
a range of empirically-based therapies, from cognitive
behavior approaches to exposure therapies, which di-
rectly target the PTSD symptomatology [for an overview
E. Martz et al. / Health 2 (2010) 332-341
Copyright © 2010 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
of the range of treatments, see 64-67]. Yet, more com-
prehensive strategies are needed, in order to address the
complex traumatic reactions (e.g., “double PTSD” [13])
that may be experienced when a disability occurs in a
9.1. Limitations
The findings of this study must be interpreted with cau-
tion. First, the generalizability of the findings obtained in
this study is limited, because the data were drawn only
from U.S. Vietnam veterans. King and King [59] pub-
lished a detailed article critiquin g possible validity issu es
related to research among Vietnam veterans. More re-
cently, debates about calculating the PTSD rates from
the NVVRS dataset have been published in several
volumes of the Journal of Traumatic Stress. The condi-
tions and uniqueness of the Vietnam war itself may have
created differences in PTSD rates among veterans of
various wars [68,69].
In addition, because this research was retrospective
and used cross-sectional data, no causal patterns can be
established. Further, the disability variab le was based on
a single, self-reported item that did not encompass the
wide range of possible disability definitions; yet, in this
secondary data analysis, the researchers determined it as
the best representation of a war injury with permanent
consequences, i.e. disability. Finally, while the percent-
age of variance explained in PTSD was notable (67%),
unexplained variance still exists, which means that vari-
ables not included in this study also are influencing
PTSD levels.
The results of this study provide unique information
contributing to the knowledge about PTSD, which has
been generated by the decades of research using data
from the NVVRS and other sources. The present re-
search examined whether disability predicted PTSD
(while controlling for specific variables), in addition
whether social support and coping were modifiers of that
association; these two issues had not yet been studied in
previous research using the N VVR S data.
As expected, medical conditions or disabilities may be
one source of the veterans’ PTSD. The findings clarified
that emotional social support and problem-solving cop-
ing both decrease the impact of perceived disability on
PTSD levels. In view of such knowledge, psychosocial,
therapeutic interventions may help to facilitate the indi-
vidual with a disability’s functioning and adaptation to
the onset of a permanent medical condition. Future re-
search should test whether the findings of this study,
which used a nationally representative data from the
Vietnam era, can be replicated among veterans from the
Iraq and Afghanistan wars.
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