The prediction of levels of posttraumatic stress levels by depression among veterans with disabilities.
PTSD is characterized by an individual's exposure to one or more events that involve death, threat to life or limb, or serious injury (APA, 2000) and a cluster of psychological responses to the memories of those events, consisting of intrusive, avoidant, and hyperarousal symptoms. Researchers have investigated the coexistence of PTSD with other psychiatric disorders, such as depressive disorders, anxiety disorders, and substance abuse (Keane & Kaloupek, 1997; Kessler, Sonnega, Bromet, & Nelson, 1995; Kulka et al., 1990; Yehuda & McFarlane, 1995). In view of the limited number of empirical studies on the association between PTSD and depression among individuals who have disabilities (Martz, 2004), the purpose of this study is to investigate whether depression predicts posttraumatic stress levels, after controlling for demographic variables, among U.S. veterans with service-connected disabilities. The following sections will briefly review selected demographic factors that have been found to be related to posttraumatic stress levels.
Age has not always been found to be a predictor of PTSD, though the trend appears to be that a younger age predicts higher posttraumatic stress levels. Cordova et al. (1995) found that among women who had received treatment for breast cancer, age was the only significant predictor of posttraumatic stress levels, with a younger age related to higher levels of posttraumatic stress. Perry, Cella, Falkenberg, Heidrich, and Goodwin (1987) found that among individuals with severe burns, those who exhibited PTSD were significantly younger than those without PTSD. Thompson (1999) found that among individuals who had experienced a myocardial infarction, age was significantly related to posttraumatic stress levels, with a younger age related to higher levels of PTSD. In contrast, Roca, Spence, and Munster (1992) indicated that age did not significantly predict posttraumatic stress levels among 43 individuals with burn injuries.
Findings are mixed on whether education level is a significant predictor of posttraumatic stress levels. The National Comorbidity Survey found education was not a significant predictor of PTSD after controlling for gender, age, and marital status (Kessler, Sonnega, Bromet, & Nelson, 1995). Breslau, Davis, Andreski, Peterson, and Schultz (1997) found that education level was not significantly associated with PTSD. Yet, Breslau et al. (1991) found that individuals with lower levels of education had a greater percentage of PTSD than those with higher levels of education.
Multiple research studies have demonstrated that, in general, women have higher rates of PTSD than men (Breslau et al., 1997; Helzer, Robins, & McEvoy, 1987; Kessler, Sonnega, Bromet, & Nelson, 1995; Zlotnick, Zimmerman, Wolfsdorf, & Mattia, 2001). Kessler and colleagues (1995) estimated that the prevalence of PTSD among American women (10.4%) was twice as likely as men (5%). In contrast to the percentages observed in a community population, the National Vietnam Veterans Readjustment Study (NVVRS) found that among Vietnam theater veterans, PTSD was more common in men (15.2%) than in women (8.5%) (Kulka et al., 1990).
Findings are mixed regarding the prevalence of PTSD in gender categories among individuals who have experienced an injury or disability. Perry, Cella, Falkenberg, Heidrich, and Goodwin (1987) found that individuals who had severe burns and PTSD were more likely to be male than those with burns and without PTSD. Roca, Spence, and Munster (1992) found that gender did not significantly predict posttraumatic stress levels among individuals with burn injuries. Powers, Cruse, Daniels, and Stevens (1994) found that gender approached significance (p = .0545) between those with PTSD and those without PTSD who had experienced burns.
Findings are mixed on whether marital status predicts PTSD. The National Comorbidity Survey found that marital status was a significant predictor of PTSD after controlling for age (Kessler, Sonnega, Bromet, & Nelson, 1995). More specifically, men and women who had been previously married (i.e., were separated, divorced, or widowed) were significantly more likely to have a lifetime prevalence of PTSD than men and women who were currently married. Further, the lifetime prevalence of PTSD, after controlling for age, was higher among married men than it was among men who had never married, which was a trend that was also true for women (Kessler, Sonnega, Bromet, & Nelson, 1995). Perry, Cella, Falkenberg, Heidrich, and Goodwin (1987) found that among individuals with severe burns, those with PTSD were significantly more likely to be married than individuals without PTSD.
Coexistence of PTSD and depression
In a community sample of 1200 young adults, Breslau, Davis, Andreski, and Peterson (1991) found the occurrence of PTSD diagnosis with another psychiatric diagnosis in 82.8% of the individuals; 36.6% had major depression along with PTSD. McFarlane and Papay (1992) found that major depression was the most common diagnosis coexisting with a PTSD diagnosis among 147 volunteer fire fighters. In a sample of 20 individuals who had experienced a motor vehicle accident and reported pain problems, Hickling and Blanchard (1992) found that five of the 10 individuals who had a diagnosis of PTSD also had Major Depressive Disorder. Shalev et al.'s (1998) prospective study on PTSD among trauma survivors with non-permanent, physical injuries who were seen in an emergency room (N = 211) found that at one month after the trauma, 44.4% of the individuals with a PTSD diagnosis had major depression. Zayfert, Becker, Unger, and Shearer (2002) found that among individuals referred for treatment for anxiety disorders (N = 310), 36% had a PTSD diagnosis, while 48% of that group had a coexisting diagnosis of Major Depressive Disorder.
In a random sample of 50 individuals who were utilizing services at the Boston PTSD Center, Keane and Wolfe (1990) found a coexistence of PTSD with major depression among 68% of this group and a coexistence with dysthymia among 34% of this sample. Roszell, McFall, and Malas (1991) found that among a sample of 48 Vietnam veterans, 64.6% had major depression concurrent with a PTSD diagnosis. Zatzick and colleagues (1997) examined data on 1,200 male Vietnam veterans and found that the odds of PTSD were 17.6 times greater among individuals who had major depression. According to Hankin, Spiro, Miller, and Kazis (1999), 55% of 2,160 U.S. veterans who had depression also had PTSD. Stein, McQuaid, Pedrelli, Lenox, and McCahill (2000) assessed for PTSD among 368 individuals who used a primary care clinic, of which 11.8% screened positive for PTSD (full or partial PTSD). Of the individuals with PTSD, 61.1% also had Major Depressive Disorder.
In view of the above research, the purpose of this study is to examine whether depression levels predict posttraumatic stress levels, after controlling for demographic variables, among veterans with disabilities.
This study involved an analysis of archival data from case records of U. S. military veterans (N = 245) with service-connected disabilities, who received services from a private provider of vocational rehabilitation services in Montana. No identifying information was provided in the archival data that would allow the researchers to connect the data with any one individual.
In this sample, 82.2% were male and 17.8% were female. The mean age of this sample was 37.5 years (SD = 9.4), ranging from 21 to 60 years old. The years of education averaged 13.07 years (SD = 1.55) and ranged from 7 to 18 years of education. The marital status included 63.3% married, 17.1% divorced, 13.3% separated, .4% widowed, and 5.9% other or no answer. Although there was a broad range of disabilities reported, 60% of this sample listed problems in the musculoskeletal system as the primary disability, followed by psychosocial (7.9%) and circulatory (5%) systems. Because many veterans reported multiple disabilities, there was no straightforward way to create a "severity of disability" composite variable from this archival database and thus, such data were not reported.
The veterans were from the following branches: 59.7% Air Force, 22.9% Army, 12.7% Navy, 4.2% Marine Corps; and .4% Coast Guard. The total years of active duty averaged 11.9 (SD = 7.9). Only part of the sample reported combat tours (N = 48). The extent of combat exposure was not available in this data. The average total years of reserve duty was minimal (M = .04, SD = .59).
Institutional Review Board (IRB) approval was obtained for the analysis of this secondary data. A separate IRB approval for primary data analysis had been given to the researcher (T. B.), who originally collected the data during his provision of vocational rehabilitation sessions to the veterans. Information from the vocational rehabilitation reports, written by T.B., was later entered into a database. All information that would enable the identification of a subject was removed from the database before the data was obtained for this study.
For this secondary data analysis, the following instruments were used:
a. Minnesota Multiphasic Personality Inventory-2 (MMPI-2): The MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) is a self-report psychological instrument consisting of 567 true-false questions. It provides 3 validity, 10 clinical scales, and supplementary scales (Graham, 2000). Three scales were used in this study: one 57-item Depression scale (D) and two supplementary scales: the 46-item Posttraumatic Stress Disorder-Keane scale [PK] (Keane, Malloy, & Fairbank, 1984), and the 60-item Posttraumatic Stress Disorder-Schlenger [PS] (Schlenger & Kulka, 1987). Though these 2 PTSD scales were originally developed among samples of combat veterans, they have subsequently been used among other veteran and civilian samples (Graham, 2000; Miller, Goldberg, & Streiner, 1995). The Cronbach's alpha in a MMPI-2 normative sample was reported as [alpha] = .85 for men and [alpha] = .87 for women in the PK scale (Graham, 2000), or [alpha] = .86 for males and [alpha] = .89 for females (Briere, 2004). Internal consistency was found to be [alpha] = .89 for men and [alpha] = .91 for women in the PS scale (Graham, 1990). Briere (2004) reported research that found a higher Cronbach's [alpha] = .95 for the PK scale. Cronbach's alpha coefficients were not available for this archival research, because the database contained total scores only for the MMPI-2 scales. Briere (2004) summarized studies that analyzed the discriminant validity of the PK and PS scales.
Standardized T scores were used in this analysis. In this sample, the PK scale M = 54.45 (SD = 14.40) and PS scale M = 54.82 (SD = 14.66). The Pearson correlation coefficient between the PK and PS scales was high, r = .96, p < .001, which was similar to the findings of Miller, Goldberg, and Streiner (1995). Both the PK and PS scales were utilized in this study as a form of cross-validating the results of the statistical analyses. Because the PK and PS scales measure PTSD symptoms, then using both scales in separate statistical analyses demonstrated whether the results of the regressions were similar for both scales.
In this study, the topic of interest was the variance of posttraumatic stress levels (as measured by the PS and PK scales of the MMPI-2) and not the existence of a PTSD diagnosis. Posttraumatic stress levels, not PTSD diagnosis, were the focus of the study for several reasons. Shalev et al. (1998) advocated for decreasing the use of categorical PTSD measures (e.g., diagnosis) and for utilizing continuous dimensions of response to trauma (e.g., posttraumatic stress levels). Researchers have cautioned that the PK and PS scales should not be the sole means of making a PTSD diagnosis, because according to some research, there is some overlap of these scales with indicators of general psychological distress (Miller, Goldberg, & Streiner, 1995; Wise, 1996). More importantly, in view of the six criteria needed to diagnosis PTSD (APA, 2000), information on factors such as an experience of an overwhelming trauma that involved threat to life or limb (Criterion A) and time since trauma (Criterion E) are not included in the PTSD scales in the MMPI-2 assessment. Thus, the MMPI2 inventory alone should not be used for a PTSD diagnosis. Although clinical cut-off scores on the PTSD scales may signal the existence of PTSD symptoms, other means of assessment should be used to make a PTSD diagnosis (Miller, Goldberg, & Streiner, 1995).
In view of the possibility that some of this sample may have over-reported PTSD symptoms to receive greater monetary compensation, it was debated whether the F scale (Infrequency scale) or the K scale (Correction or Subtle Defensiveness scale) of the MMPI-2 should be utilized in this study to detect "malingering." Yet, multiple studies have indicated that individuals who have experienced trauma demonstrated elevated F scales, due to managing a greater level of psychological distress (see Elhai, Ruggiero, Frueh, Beckham, & Gold, 2002). Further, Elhai et al. (2002) reported an overlap of items of the PK and PS with the K scale, which may elevate K scores if people expressed reactions to trauma. Therefore, the use of the F or K scales among a population who has experienced trauma (such as a disability) appeared problematic and thus, was not used in this research. b. Demographics: Demographic information, such as age, education, gender, and marital status, was collected during interviews by the provider (T. B.) of vocational rehabilitation services.
Two hierarchical multiple regression analyses were run with the two PTSD scales (as measured by the PK and PS scales of the MMPI-2) as the separate dependent variables. For each regression, the independent variables were entered in two blocks, in order to control for the influence of the demographic variables. The first block contained the following demographic variables: age, education, gender, and marital. The second block contained only the depression variable (as measured by the D scale of the MMPI-2). In each of the multiple regression analysis of one PTSD scale, the block of demographic variables was not significant (see Table 1), nor were the regression coefficients of the demographic variables significant in this step in both analyses.
With the addition of depression in the second step of the regression, the variance explained in each of the PTSD scales (see Table 1) became significant. In each of the regression equations, depression had a significant regression coefficient. Depression explained 44% of the variance in the PK scale and 46% of the variance in the PS scale after controlling for demographic variables.
The purpose of this study was to examine whether depression levels predicted posttraumatic stress levels after controlling for demographic variables. The results indicated that depression explained almost half (44-46%) of the variance in PTSD levels among veterans with disabilities, over and above the insignificant variance explained by demographic variables. These relatively strong results among veterans with disabilities concur with the findings regarding the elevated co-occurrence of depression and PTSD among a veteran population in general (Hankin, Spiro, Miller, & Kazis, 1999; Keane & Wolfe, 1990; Roszell, McFall, & Malas, 1991; Stein, McQuaid, Pedrelli, Lenox, & McCahill, 2000). These findings also are in accordance with the few studies that have examined the coexistence of depression and PTSD among individuals with disabilities or severe injuries (Hickling & Blanchard, 1992; Martz, 2004; Shalev et al., 1998).
This study provides more information about ability of depression to predict the existence of posttraumatic stress levels among veterans with disabilities. It is also noteworthy that all of the four demographic variables (age, education, ethnicity, and marital status) predicted an insignificant amount of posttraumatic stress levels in this study. This indicated that posttraumatic stress levels, in general, were not more elevated in certain subgroups of this sample, when making comparisons by demographics.
Having elevated posttraumatic stress levels may interfere with the rehabilitation process (Keim, Malesky, & Strauser, 2003; Strauser & Lusting, 2001). Thus, it is important for rehabilitation counselors to become more cognizant of PTSD and what factors may increase the likelihood of elevated posttraumatic stress levels. Awareness of PTSD is growing in the field of rehabilitation counseling. Penk and Flannery (2000) wrote a multifaceted chapter about psychosocial rehabilitation, suggesting some specific techniques to use in order to pormote coping with traumatic memories. Strauser and Lusting (2001) and Martz (2001a, 2001b) wrote about PTSD in the context of disability and vocational rehabilitation.
This study indicates that higher levels of depression in rehabilitation clients significantly predicted elevated levels of posttraumatic stress. Rehabilitation counselors can use these findings as a guidepost for what kind of psychological assessments (e.g., an assessment for PTSD) should be requested for their rehabilitation clients. Thus, rehabilitation counselors should consider requesting an assessment for PTSD if they notice elevated depression in their clients.
This archival research is limited in several ways. The sample included only veterans with disabilities who utilized vocational rehabilitation services in Montana. The sample also was composed primarily of males. This constricts the generalizability to a similar population and geographical area.
Due to the correlational nature of this study, the hypothesis that depression levels predicted posttraumatic stress levels could have been reversed (i.e., posttraumatic stress levels predicting depression). Such a reversal would have given different information; but the authors wanted to focus in the study on PTSD and its ramifications. Further, because this research was archival, no connections could be made between posttraumatic stress levels and the type of trauma that triggered posttraumatic reactions. Many kinds of traumatic events, other than military events or disability, may have caused PTSD symptoms.
The results of this study indicated that depression levels predicted almost half of the fluctuation in PTSD levels among veterans with disabilities after controlling for demographic variables. A clinical implication of these results is that if a veteran with a disability exhibits some form of depression, then the possibility of the simultaneous existence of posttraumatic stress symptoms should be investigated. Such knowledge can provide more information and understanding about the client's psychological status, which rehabilitation counselors can utilize to facilitate movement toward psychological adjustment.
Table 1 Hierarchical multiple regression of PTSD levels Adj. [DELTA] = Variable/step [R.sup.2] [R.sup.2] [R.sup.2] PK Scale Step 1 .01 -.01 .01 Marital [beta] = .08 Gender [beta] = -.05 Age [beta] = -.04 Education [beta] = -.06 Step 2 .45 .44 .44 Depression [beta] = .67 * PS Scale Step 1 .02 .00 .02 Marital [beta] = .13 Gender [beta] = -.05 Age [beta] = .02 Education [beta] = -.04 Step 2 .48 .47 .46 Depression [beta] =.68 * Variable/step F df [DELTA] = F PK Scale Step 1 .76 4,210 .76 Marital [beta] = .08 Gender [beta] = -.05 Age [beta] = -.04 Education [beta] = -.06 Step 2 34.14 5,209 165.33 * Depression [beta] = .67 * PS Scale Step 1 1.18 4,210 1.18 Marital [beta] = .13 Gender [beta] = -.05 Age [beta] = .02 Education [beta] = -.04 Step 2 39.01 5,209 186.17 * Depression [beta] =.68 * * Significant at p < .01
We would like to thank Stephen Leierer, Ph.D., Kristy Brumfield, and Niki Termine, from Louisiana State University Health Sciences Center, for help with data management.
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University of Missouri, Columbia
University of Missouri, Columbia
Terry L. Blackwell
Louisiana State University
Erin Martz, Ph.D., C.R.C., Rehabilitation Counseling Program, Educational, School, and Counseling Psychology Department, 4B Hill Hall, University of Missouri, Columbia, MO 65211-2130 Email: firstname.lastname@example.org
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|Author:||Blackwell, Terry L.|
|Publication:||The Journal of Rehabilitation|
|Date:||Jan 1, 2005|
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