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Psychiatric diagnoses, comorbidity, and functioning in National Guard troops deployed to Iraq
Journal of Psychiatric Research 45 (2011) 126e132
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Journal of Psychiatric Research journal homepage: www.elsevier.com/locate/psychires
Psychiatric diagnoses, comorbidity, and functioning in National Guard troops deployed to Iraqq Shannon M. Kehle a, b, c, Madhavi K. Reddy b, d, Amanda G. Ferrier-Auerbach b, c, Christopher R. Erbes b, c, Paul A. Arbisi b, c, Melissa A. Polusny a, b, c, * a
Center for Chronic Disease Outcomes Research, Minneapolis, MN, USA Minneapolis VA Medical Center, Minneapolis, MN, USA University of Minnesota Medical School, Minneapolis, MN, USA d Alpert Medical School of Brown University, Providence, RI, USA b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 18 January 2010 Received in revised form 3 May 2010 Accepted 7 May 2010
Objective: Over 1.8 million troops have been deployed to Iraq (OIF) and Afghanistan. Estimates of mental health problems postdeployment have been based on screening instruments; no studies have examined the postdeployment mental health of troops returning from OIF using structured diagnostic interviews. The goal of the current study is to (a) report on rates of mental health diagnoses and comorbidity in soldiers after deployment to OIF using clinical interviews, and (b) examine the relationship between mental health diagnoses and overall functioning and quality of life. Method: Participants were 348 National Guard soldiers drawn from the Readiness and Resilience in National Guard Soldiers (RINGS) study, a longitudinal study of mental health after deployment to OIF from March 2006 to July 2007. Participants completed clinical interviews, including the Clinician Administered PTSD Scale and the Structured Clinical Interview for the DSM-IV, and self-report measures of social adjustment and quality of life 6e12 months following deployment. Results: Most participants did not meet criteria for a mental health diagnosis. Non-PTSD anxiety disorders and depressive disorders were the most common. Mental health diagnoses were associated with poorer functioning and quality of life. PTSD had the strongest relationship with social functioning and quality of life. For those with PTSD, comorbid diagnoses were not associated with an incremental decrease in functioning or quality of life. Conclusions: The findings highlight the significant rate and burden of mental health disorders among this population and suggest that while PTSD is relatively uncommon, it is a particularly deleterious disorder. Published by Elsevier Ltd.
Keywords: Posttraumatic stress disorder (PTSD) Trauma Military Psychiatric diagnosis Quality of life
In recent years there have been increasing concerns regarding the mental health of American soldiers returning from the current wars in Afghanistan (OEF) and Iraq (OIF). Early data suggest high rates of posttraumatic stress disorder (PTSD), depression, and alcohol problems among OEF/OIF soldiers (Hoge et al., 2004, 2006; Jacobson et al., 2008; Seal et al., 2007). To date, most reports of OEF/ OIF postdeployment mental health diagnoses involve rates of probable diagnoses based on the use of self-report measures (Grieger et al., 2006; Hoge et al., 2004, 2006). Using such methodology, estimated rates in returned OEF/OIF military personnel have been reported at up to 25% for PTSD, 13% for depression, and
q This research has not been previously published or presented in any form. * Corresponding author. Minneapolis VA Medical Center (116A9), One Veterans Drive, Minneapolis, MN 55417, USA. Tel.: þ1 (612) 725 2000x3965; fax: þ1 (612) 727 5633. E-mail address: [email protected] (M.A. Polusny). 0022-3956/$ e see front matter Published by Elsevier Ltd. doi:10.1016/j.jpsychires.2010.05.013
12% for alcohol-related disorders (Jacobson et al., 2008; Milliken et al., 2007). The RAND Corporation recently conducted a large epidemiological study of nearly 2000 OEF/OIF soldiers and estimated rates of both PTSD and major depression to be 14% (Tanielian and Jaycox, 2008). While useful because of their ease of administration, self-report assessment tools often result in inaccurate diagnoses and overestimates of illness (Lowe et al., 2004; Terhakopian et al., 2008). Structured clinical interviews, while time intensive, are widely considered to be the most accurate way of diagnosing mental health conditions. We have previously explored rates of postdeployment PTSD in our sample and found that 7% of the troops met criteria using the Clinician Administered PTSD Scale (CAPS; Blake et al., 1995; Erbes et al., under review). To our knowledge, no study has examined the rate of other mental health diagnoses or comorbidity, as assessed by structured clinical interviews, in military personnel who have recently returned from OEF/OIF. Thus, the goal of this paper is to provide the first known report of rates of
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mental health disorders and comorbidities, as diagnosed by structured clinical interviews, in a sample of U.S. National Guard troops who have recently returned from OIF. Additionally, this paper will report on how mental health diagnoses impact the social functioning of these troops. Research conducted with veterans of previous wars has shown that postdeployment mental health disorders are associated with impairments in functioning, decreased quality of life, increased health care costs, and significant financial burdens (The Iowa Persian Gulf Study Group, 1997; Jordan et al., 1991; Kang et al., 2003; Prigerson et al., 2002). PTSD alone is associated with an estimated $3 billion dollars of lost productivity per year, an average 3.6 days of work lost per month, a lowered likelihood of veterans working for pay, and a negative impact on veterans’ wages (Kessler, 2000; Savoca and Rosenheck, 2000). In regards to OEF/OIF, the two-year cost of postdeployment PTSD and major depression is estimated to be between $4.0 and $6.2 billion dollars (Tanielian and Jaycox, 2008). Further, rates of comorbidity among individuals with PTSD have been estimated to be as high as 99% (Kulka et al., 1990) and previous studies have shown the negative impact of PTSD is even greater when another mental health diagnosis is present (Kessler and Frank, 1997). In line with previous research, we expected that soldiers who report a mental health diagnosis will report greater negative impact on their functioning, and that comorbid mental health diagnoses will have a cumulative negative impact on the soldiers’ functioning. 1. Materials and methods The National Guard command and the institutional review boards of the University of Minnesota Medical School, Minneapolis Veteran’s Affairs Medical Center, and Department of Defense approved the study protocol. The investigation was conducted in accordance with the latest version of the Declaration of Helsinki and written informed consent was obtained from participants prior to study enrollment and interview administration. 1.1. Participants and procedures The study sample was drawn from the Readiness and Resilience in National Guard Soldiers (RINGS) Study, a longitudinal investigation of risk and resilience factors predictive of postdeployment mental health in troops deployed to OIF. Soldiers from a National Guard Brigade Combat Team (BCT) were surveyed one month prior to a 16-month deployment to Iraq and again 3 months following return from deployment. As part of the postdeployment survey, a variety of psychological and deployment-related factors, including quality of life and social adjustment, were assessed using standard mailed survey methodology. All participants were also invited to complete a postdeployment diagnostic interview. Interviews were conducted between 6 and 12 months following troops’ return from Iraq. Participants were compensated $130 for completing the interview. Fig. 1 details participation rates. Participants were originally contacted approximately one month prior to deployment to OIF while completing a six-month mobilization training. Over the course of approximately 2½ weeks, soldiers were invited through unit announcements and flyers to attend a group briefing session held by investigators. Ultimately, 522 of the approximately 2600 individuals in the total brigade completed the predeployment survey. Those who participated predeployment were demographically similar to the larger brigade (Table 1). Of the 522 soldiers who participated predeployment, 424 participants (81%) completed the follow-up survey. Postdeployment responders and non-responders did not differ on gender, ethnicity, or self-reported predeployment
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distress. The responders were more likely to be officers (responders ¼ 11%; non-responders ¼ 4%), c2 (1, N ¼ 522) ¼ 4.43, p < 0.05, married (responders ¼ 49%; non-responders ¼ 31%), c2 (1, N ¼ 522) ¼ 10.65, p < 0.001, and older (responder M ¼ 29.9, SD ¼ 8.8; non-responder M ¼ 25.6, SD ¼ 6.9), t(520) ¼ 4.46, p < 0.001, than the non-responders. Eighty-two percent (n ¼ 348) of postdeployment survey responders completed a diagnostic interview. Seven participants completed an interview but not a follow-up survey and were excluded from current analyses. There were no differences between soldiers who completed or did not complete the interview on age, ethnicity, marital status, enlisted status, self-reported distress, social adjustment, or quality of life. Soldiers completing interviews were more likely to report some college education (c2 ¼ 12.96, p < 0.001). Of those completing interviews, 248 soldiers (71%) were interviewed in-person and 100 soldiers (29%) were interviewed via telephone. There were no differences between those interviewed in-person or by phone on demographics (age, ethnicity, marital status, level of education), postdeployment PTSD or depressive symptomology, number of diagnoses, quality of life, or social adjustment. Female soldiers were more likely to participate inperson than by telephone (c2 ¼ 9.49, p ¼ 0.002). 1.2. Measures The Clinician Administered PTSD Scale (CAPS; Blake et al., 1995), considered to be the “gold standard” of PTSD diagnosis, consists of 30-items, and corresponds to the Diagnostic and Statistical Manual of Mental Disorders 4th Edition (DSM-IV-TR; American Psychiatric Association, 2000) criteria for PTSD. Using original CAPS scoring criteria (Blake et al., 1990), PTSD was diagnosed for participants who experienced a traumatic event (criteria A1), reported at least one reexperiencing symptom, three avoidance symptoms, and two hyperarousal symptoms each at a frequency rating of at least 1 and an intensity rating of at least 2, and reported and significant impairment or distress. Subthreshold PTSD was diagnosed for participants who experienced a traumatic event (criteria A1), reported at least one avoidance, one reexperiencing, and one hyperarousal symptoms at a frequency rating of at least 1 and an intensity rating of at least 2, and reported significant impairment or distress (Stein et al., 1997). Additional Axis I disorders were diagnosed with the SCID-I/NP (Non Patient-Edition) Research Version interview (First et al., 2002). The following modules were administered: Overview, Mood Episodes, Psychotic Disorders, Mood Disorders, Substance Use Disorders, Anxiety Disorders (with exception of PTSD questions), and Somatoform Disorders. Selfreport survey data analyzed for the present report were collected by two instruments: the Social Adjustment Scale-Self-Report (SASSR; Weissman, 1999) and Navy Quality of Life Survey (NQOLS; Wilcove et al., 2003). The SAS-SR contains 54-items which assess individual’s functioning in 6 areas: work, social and leisure activities, relationships with extended family, role as a marital partner, parental role, and role within the family unit including economic functioning perceptions. Each item is rated on a five point Likert scale, with higher scores indicating greater impairment. A domainbased approach for assessing soldiers’ quality of life was adapted from the NQOLS. Domains assessed include leisure and recreation, friends and friendship, relationship with relatives, marriage/intimate relationships, relationships with children (if applicable), standard of living, and overall satisfaction with life experiences. Each item is rated on a seven point Likert scale, with higher scores indicating greater satisfaction. We also used the “combat experiences” subscale of the Deployment Risk and Resilience Inventory to assess the presence or absence of a range of combat experiences (King et al., 2006).
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1/34 BCT (N = 2600)
Predeployment Survey (n = 522) Postdeployment Survey Non-Responders (n = 98) Postdeployment Survey (n = 424)
n=7
Interview Non-Completers (n = 76)
Clinical Interviews (n = 355)
In-Person Interviews (n = 248)
Telephone Interviews (n = 100)
Fig. 1. Flow of subjects through data collection.
1.3. Interviewer training and reliability
1.4. Data analysis
Interviews were conducted by a team of eight doctoral level graduate students who completed extensive training and ongoing clinical supervision. Training included a day-long didactic lecture, viewing of administration training tapes, and the completion of “check-out” interviews. To ensure quality of the interviews and prevent drift, refresher training was held for all interviews after approximately three months. All interviewers participated in weekly supervision provided by the investigators at which time interviews were reviewed, and consensus diagnoses were established. All interviews were digitally recorded for reliability purposes. Ten percent of interviews were reviewed and independently rated by a second interviewer. Inter-rater reliabilities for individual diagnoses from the SCID ranged from 0.56 to 1.0. Across all diagnostic categories, inter-rater reliability for the SCID was moderate to good (kappa ¼ 0.67). Reliability for the CAPS was also evaluated across symptom ratings, yielding an interclass correlations coefficient of 0.88.
Pearson chi-square tests were used to examine differences in diagnosis by gender and age category. Logistic regressions were conducted to examine the relationship between each of the diagnostic groups in Table 2 and associated social functioning and quality of life. The comparison group for each of the regressions was the no diagnosis group. With the exception of the no diagnosis group, diagnostic groups were not mutually exclusive because participants could have had more than one diagnosis. Odds ratios (OR), 95% confidence intervals (CI), and p-values are reported for each of the logistic regression comparisons. All continuously distributed variables were converted to z-scores prior to entry into the regression models. Thus, the OR represents the factor by which the odds of having a specific disorder changes in conjunction with a standard deviation difference in the independent variable (e.g. total social functioning). Cohen’s d effect sizes were also calculated for each comparison. The effect sizes can be interpreted using Cohen’s definition of small (0.2), medium (0.5), and large (0.8) effects (Cohen, 1988).
S.M. Kehle et al. / Journal of Psychiatric Research 45 (2011) 126e132 Table 1 Demographic characteristics of interview participants, overall readiness and Resilience in National Guard Soldiers (RINGS) cohort at baseline, and the Brigade Combat Team population. Demographic characteristic
Overall cohort at baseline (n ¼ 522)
Panel participants at follow-up (n ¼ 348)
Brigade Combat Team population (n ¼ 2573)
Sex Male, No. (%)a Female, No. (%)
462 (88) 60 (12)
304 (87) 44 (13)
2339 (91) 234 (9)
Age, mean (SD), y 18e29 years, No. (%) 30þ years, No. (%)
29.1 (8.6) 313 (60) 209 (40)
31.3 (9.5) 170 (49) 172 (51)
1672 (65) 901 (35)
484 (93)
325 (93)
2407 (95)
37 (7)
23 (7)
134 (5)
Rank Enlisted, No. (%) Officer, No. (%)
471 (90) 51 (10)
303 (87) 44 (13)
2301 (90) 270 (10)
Marital status Married, No. (%) Not married, No. (%)
237 (45) 285 (55)
173 (48) 163 (52)
1006 (40) 1515 (60)
Race/ethnicity White, non-Hispanic, No. (%) Non-white, No. (%)
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OEF/OIF. Troops reported substantial exposure to combat and other potentially traumatic war-related events. A large majority of soldiers (91%) reported participating in combat missions or patrols, 94% reported that they or a member of their unit received incoming small arms fire, 55% were attacked by terrorists or civilians, and 22% thought they killed someone in combat. Ten percent of the sample reported being wounded or injured during deployment. 2.2. Rates of postdeployment psychiatric diagnoses
b
a Percentages reported are the proportion of individuals within each demographic subgroup who reported the outcome. b Mean age for the brigade was not available.
Rates of psychiatric comorbidity were calculated for the entire panel, for participants with a diagnosis of PTSD, and for participants with a diagnosis of either PTSD or subthreshold PTSD. For the entire panel, we conducted one-way analysis of covariance (ANCOVA) to examine the association between total number of diagnoses and overall social functioning and quality of life. We then conducted a second ANCOVA to examine the relationship between having no diagnosis, one diagnosis, or two or more diagnoses and overall social functioning and quality of life. Next, using only those with either PTSD or subthreshold PTSD, we again conducted an ANCOVA to examine the association between number of diagnoses and overall social functioning and quality of life. Finally, using only those with PTSD or subthreshold PTSD, we conducted an ANCOVA to examine the association between having a comorbidity (yes/no) and total social adjustment and overall quality of life. Due to a response bias within our sample, we controlled for marital status, education level, age, and enlisted status in the regressions and ANCOVAs. 2. Results 2.1. Sample characteristics and deployment experiences Interview completers were 87% male, 93% Caucasian, 50% married, 87% enlisted rank, with a mean age of 31.30 (SD ¼ 9.5) years (Table 1). Four percent of the sample had a previous deployment to
Table 2 displays rates of postdeployment psychiatric disorders. A majority (62%) of the sample did not meet criteria for a current psychiatric disorder at the time of assessment. Depressive disorders were the most common diagnoses; major depressive disorder was the most frequent diagnosis in that category (n ¼ 41). Non-PTSD anxiety disorders (other anxiety) and alcohol use disorders were also relatively common. The most frequent disorders in the other anxiety category were anxiety disorder not otherwise specified (NOS; n ¼ 20), social anxiety disorder (n ¼ 11), and generalized anxiety disorder (n ¼ 9). Of those who met criteria for an alcohol use disorder, 73% were diagnosed with dependence. As we have previously reported, 7% of the sample met criteria for PTSD (Erbes et al., under review). When those with subthreshold PTSD were included, the sample prevalence increased to 15%. Pain disorder, somatization disorder NOS, and psychotic disorder NOS were each diagnosed in one participant; these disorders were not included in the analyses due to their low prevalence in the sample. Women were more likely than men (52% vs 36%) to have a psychiatric diagnosis, c2 ¼ 4.40, p ¼ 0.04. Specifically, female soldiers were more frequently diagnosed with PTSD (14% vs 6%; c2 ¼ 4.03, p ¼ 0.04), depressive disorders (27% vs 13%; c2 ¼ 6.41, p ¼ 0.01), and non-PTSD anxiety disorders (25% vs 12%; c2 ¼ 6.10, p ¼ 0.01). Age was not significantly associated with the presence of any diagnosis. 2.3. Functioning and quality of life associated with psychiatric diagnoses Table 3 displays the association between psychiatric diagnoses and overall functioning and quality of life among the panel of OIF deployed troops. Drug use disorder was eliminated from these analyses due the small number of cases. Only participants in an intimate relationship (n ¼ 157) were included in the marriage/ intimate relationship analyses, while only those with children (n ¼ 123) were included in the analyses related to parenting. Having a diagnosis of PTSD (M ¼ 2.19, SD ¼ 0.39), subthreshold PTSD (M ¼ 2.17, SD ¼ 0.56), depressive disorder (M ¼ 2.14, SD ¼ 0.48), non-PTSD anxiety disorder (M ¼ 2.00, SD ¼ 0.41), or alcohol use disorder (M ¼ 1.98, SD ¼ 1.20) was associated with lowered social functioning when compared with those without
Table 2 Rates of psychiatric diagnoses among National Guard soldiers approximately six months following OIF deployment. PTSD
Subthreshold PTSD
Depressive disorders
Other anxiety
Alcohol use disorders
Drug use disorders
Total n (%)a
23/348 (7)
30/348 (9)
51/348 (15)
46/348 (13)
45/348 (13)
4/348 (1)
216/348(62)
Gender Male Female
17/304 (6) 6/44 (14)
25/304 (8) 5/44 (11)
39/304 (13) 12/44 (27)
35/304 (12) 11/44 (25)
38/304 (13) 7/44 (16)
3/304 (1) 1/44 (2)
195/304 (64) 21/44 (48)
Age 18e29 30e39 40e49 50e59
14/170 6/110 3/48 0/14
20/170 6/110 3/48 0/14
25/170 16/110 7/48 3/14
18/170 17/110 7/48 3/14
23/170 15/110 6/48 0/14
1/170 3/110 0/48 0/14
105/170 67/110 32/48 9/14
(8) (6) (6) (0)
(12) (6) (6) (0)
(15) (15) (15) (21)
Abbreviations: PTSD, posttraumatic stress disorder. a Rows do not sum because participants can have more than one diagnosis.
(11) (16) (15) (21)
(14) (14) (13) (0)
(1) (3) (0) (0)
No diagnosis
(62) (61) (67) (64)
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Table 3 Self-reported functioning and quality of life associated with psychiatric diagnoses among National Guard soldiers PTSDa
Subthreshold PTSD
Depressive disorders
Other anxiety
Alcohol use disorders
Any diagnosis
2.76** (1.92e3.99) 0.47** (0.34e0.65)
2.19** (1.53e3.15) 0.50** (0.35e0.70)
2.12** (1.45e3.10) 0.59 (0.43e0.81)**
2.16** (1.67e2.80) 0.53** (0.41e0.67)
b
Adjusted odds ratios (95% confidence intervals) Total SAS-SR 3.03** (1.83e5.00) 2.58** (1.71e3.88) Total NQOLS 0.43** (0.28e0.66) 0.44** (0.31e0.64)
Abbreviations: PTSD, posttraumatic stress disorder; SAS-SR, social adjustment scale e self-report; NQOLS, Navy quality of life scale. *p < 0.05. **p < 0.01. a Reference group for all comparisons was no diagnosis. b Adjusted for age, marital status, education level, and enlisted status.
a diagnosis (M ¼ 1.72, SD ¼ 0.35). In regards to PTSD, after adjusting for age, marital status, enlisted status, and educational level, the odds of having PTSD increased three-fold for each standard deviation increase in impairment on the total social functioning score (Table 3). Impairments in social and leisure activities, extended family relationships, and family role functioning were significantly associated with all diagnostic categories Impairment in selfreported functioning as a marital/intimate partner was associated with all diagnoses except PTSD and subthreshold PTSD. Parental role functioning was not associated with any diagnoses. Overall quality of life was negatively associated with having a diagnosis of PTSD (M ¼ 4.35, SD ¼ 1.04), subthreshold PTSD (M ¼ 4.44, SD ¼ 1.26), depressive disorder (M ¼ 4.63, SD ¼ 1.09), non-PTSD anxiety disorder (M ¼ 4.81, SD ¼ 0.99), or alcohol use disorder (M ¼ 4.90, SD ¼ 1.20) when compared with those without a diagnosis (M ¼ 5.48, SD ¼ 0.94). In regards to PTSD, for each standard deviation change in satisfaction with quality of life (representing increased satisfaction), the odds of having PTSD decreased by a little over one-half (Table 3). Decreased quality of life in leisure and recreational activities, relationships with relatives, and standard of living were significantly related to all diagnostic categories. Decreased quality of life related to friends and friendship was associated with all diagnoses except alcohol use disorder. The subdomain of marriage/intimate relationships was significantly, negatively related to all diagnostic categories but PTSD and non-PTSD anxiety disorders. Finally, decreased satisfaction with relationships with children was only associated with PTSD and the depressive disorders. An examination of effect sizes revealed that PTSD had the largest association with disruptions in social functioning and quality of life. PTSD (d ¼ 1.27 and d ¼ 1.14 respectively), subthreshold PTSD (d ¼ 0.96 and d ¼ 0.94), and depressive disorders (d ¼ 0.99 and d ¼ 0.84) all had large associations with overall social functioning and quality of life. The effect sizes for non-PTSD anxiety (d ¼ 0.73 and d ¼ 0.69) and alcohol use disorders (d ¼ 0.29 and d ¼ 0.54) were in the small to medium range. 2.4. Rates of psychiatric comorbidity Twenty-three percent of the sample had only one diagnosis, 10% had two diagnoses, 3% had three diagnoses, and 2% had four or more diagnoses. Among participants with PTSD, the average number of diagnoses was 1.74 (SD ¼ 1.36) with a range of zero to five. Eighty-seven percent of those with PTSD had at least one additional diagnosis; 44% had one, 17% had two, 13% had three, and 13% had four or more comorbid diagnoses. Table 4 shows rates of specific comorbid diagnoses among participants with a diagnosis of PTSD and a diagnosis of either PTSD or subthreshold PTSD. 2.5. Impact of psychiatric comorbidity on functioning and quality of life For the entire panel, a one-way ANCOVA showed that number of diagnoses was associated with impairments in overall social
functioning, F(6, 337) ¼ 9.97, p < 0.001, and quality of life, F(6, 337) ¼ 8.79, p < 0.001. When we categorized participants into three groups (no diagnosis, one diagnosis, two or more diagnoses), we again found that number of diagnoses was associated with impairments in both overall social functioning F(2, 341) ¼ 28.95, p < 0.001 and quality of life F(2, 341) ¼ 25.49, p < 0.001. Posthoc tests (Least Significant Difference) showed that each group differed significantly from each other (p 0.002). For those with a diagnosis of PTSD or subthreshold PTSD, a one-way ANCOVA showed that additional diagnoses were not related to further impairments in total functioning, F(5, 37) ¼ 1.66, p ¼ 0.22, or overall quality of life, F(5, 37) ¼ 0.24, p ¼ 0.64. Similarly, among individuals with PTSD or subthreshold PTSD, there were no significant differences in social functioning, F(1, 41) ¼ 0.002, p ¼ 0.96, or quality of life, F(1, 41) ¼ 0.44, p ¼ 0.44, between those with and without comorbid disorders.
3. Discussion We found that a majority of National Guard soldiers recently returned from a combat deployment to Iraq did not meet criteria for a mental health disorder. However, overall rates were higher in this panel than in epidemiological studies of community dwelling residents, in which overall past-year prevalence among adults has ranged from 20 to 30% (Kessler et al., 1994; Narrow et al., 2002; Reiger et al., 1984). Rates of disorders were also substantially higher in this postdeployment sample than in an epidemiological study of a general, non-OIF deployed, military cohort (Riddle et al., 2007). The soldiers had slightly higher rates than community and non-deployed military samples across all diagnoses, with the exception of drug use disorders. Not surprisingly, the greatest elevation was in PTSD, which was double the population estimate of 3.6% (Kessler et al., 1994; Narrow et al., 2002). However, the rate of PTSD in our panel was similar to what has been observed in other trauma exposed populations (Breslau et al., 1998), and to recent estimates of PTSD among Vietnam veterans. While the National Vietnam Veterans’ Readjustment Study (NVVRS) originally estimated that 15.2% of Vietnam veterans met criteria for PTSD approximately 10 years after the end of the war (Kulka et al., 1990), reanalyses of those data resulted in an estimated prevalence of 9.7% (Dohrenwend et al., 2006). While rates of PTSD in our sample were lower than in other studies of OIF soldiers that relied on self-report measures, self-report measures of depression and alcohol use disorders yielded rates similar to those in our panel (Hoge et al., 2004; Jacobson et al., 2008; Milliken et al., 2007). Finally, comorbidity was common. More than 85% of soldiers with a diagnosis of PTSD had at least one additional mental health diagnosis, with depressive disorders being the most common. These findings are similar to PTSD comorbidity rates in both the community and among Vietnam veterans, which have estimated lifetime comorbidity between 60 and 99% (Breslau et al., 1991; Davidson et al., 1991; Kessler et al., 1995; Kulka et al., 1990). Over one-half of female soldiers had a mental health diagnosis and female soldiers were significantly more likely to have a mental health diagnosis than male soldiers. Specifically, in our panel,
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Table 4 Rates of comorbidity among National Guard soldiers with a diagnosis of PTSD.
PTSD diagnosis n (%)a PTSD or subthreshold PTSD diagnosis n (%)a
Depressive disorders
Other anxiety
Alcohol use disorders
Drug use disorders
No comorbid diagnosis
16/23 (70) 27/53 (51)
8/23 (35) 15/53 (28)
5/23 (22) 10/53 (19)
0/23 (0) 1/53 (2)
3/23 (13) 10/53 (19)
Abbreviations. PTSD, posttraumatic stress disorder. a Rows do not sum because participants can have more than one comorbid diagnosis.
women were diagnosed with PTSD, depressive disorders, and non-PTSD anxiety disorders at twice the rate of men. These discrepancies are in line with epidemiological studies (both general population and military); however, the overall rate of mental health disorders among female soldiers is substantially higher than in females in the general population (Kessler et al., 1994). Further, these data reflect a shift in the roles and outcomes of deployed female soldiers, as data from NVVRS revealed that female Vietnam veterans had PTSD at one-half the rate of their male counterparts (Turner et al., 2007). Given this finding, the impact of combat deployments on female soldiers’ mental health will be an important area of future study. Soldiers with a mental health diagnosis reported significant impairments in both social functioning and quality of life. All of the diagnostic categories were related to substantial impairments and decreased quality of life. However, PTSD was associated with the greatest impairments. Among Vietnam veterans, PTSD has been associated with impaired social and familial role functioning, poor health status, diminished well-being, and disruptions in work functioning (Carroll et al., 1985; Jordan et al., 1992; Zatzick et al., 1997). Our data suggest that the presence of PTSD is associated with similar problems among OIF soldiers as early as six months postdeployment. Contrary to our hypotheses, psychiatric comorbidity among soldiers with PTSD was not related to further impairments in social functioning or quality of life. However, having more than one diagnosis was related to higher levels of impairment in the full panel. Previous epidemiological and clinic-based studies have found that having more than one psychiatric diagnosis is associated with a greater disturbance in functioning and quality of life (Kessler and Frank, 1997; Olfson et al., 1997; Ormel et al., 1994). While it is important to view the results regarding PTSD as preliminary due to the small number of participants with PTSD, it may be that among this population, PTSD is particularly debilitating and those with PTSD are already experiencing such large disruptions that a “floor effect” may be occurring, in which comorbid diagnoses do not further reduce quality of life and social functioning. This study has a number of strengths, including the use of goldstandard clinical interviews and a large non-treatment seeking population. However, participants were self-selected. Thus, while the panel demographics are similar to that of the overall brigade, this was not an epidemiological study and results may not generalize either to other National Guard units or the larger military population. Further, although our analyses suggest few differences between responders and non-responders and we attempted to control for response bias in the analyses, the findings may have been influenced by either postdeployment survey or interview response biases. Our panel also had a very small number of soldiers with previous OEF/OIF deployments. The relationship between multiple deployments, psychiatric diagnoses, and functioning is an important area of future study. Also, a number of our diagnostic conditions had few participants, thus, we may have been underpowered to find differences between groups, particularly for analyses examining intimate relationships and parenting. Conclusions regarding functioning and quality of life are based on self-report and must be considered preliminary. It is possible that the selfreport items measured a general sense of well-being, rather than
specific domains of functioning. As such, the findings require further objective validation (e.g. collateral reports; objective work performance data) in a larger sample. Finally, it is important to note that we do not have predeployment diagnostic data, thus, we cannot conclude that the disorders are the result of deployment to a combat zone. Rather, the study highlights the overall postdeployment mental health burden of soldiers deployed to OIF. This study is the first to provide diagnostic data for a community sample of OIF soldiers. The data highlight the significant rate and burden of mental health disorders among this population. Further, while PTSD appears to be particularly deleterious, it is also relatively uncommon. Thus, the findings highlight the importance of successfully identifying and treating a range of mental health problems, not only PTSD, in returning soldiers. If untreated, these disorders may have devastating effects, both for the soldier and for society. Contributors Shannon Kehle participated in study conceptualization and design, analysis and interpretation of data, drafting and revision of the manuscript, and statistical analysis. Madhavi Reddy participated in acquisition of data, drafting and revision of the manuscript, and administrative support. Amanda Ferrier-Auerbach participated in study conception and design, drafting and revision of the manuscript, and administrative support. Christopher Erbes participated in study conceptualization and design, acquisition of data, supervision, revision of the manuscript, and obtaining funding. Paul Arbisi participated in study conceptualization and design, acquisition of data, supervision, revision of the manuscript, administrative support, and obtaining funding. Melissa Polusny participated in study conceptualization and design, acquisition of data, supervision, analysis and interpretation of data, revision of the manuscript, and obtaining funding. Role of funding source This research was supported by the Minneapolis VA Medical Center Research Service and grants to Melissa A. Polusny, PhD, from Minnesota Medical Foundation (Grant #3662-9227-06) and Department of Defense Congressionally Directed Medical Research Program (CDMRP) (W81XWH-07-2-003) and a grant to Christopher R. Erbes, PhD, from the Department of Veterans Affairs Health Service Research and Development program (RRP 08-385). None of the sponsors had any role in the following: design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript. Conflict of interest All authors declare that they have no conflicts of interest. Acknowledgements The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of Veterans Affairs, Department of the Army, or the Department of Defense. This material is supported in part by the Department of
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Veterans Affairs, Veterans Health Administration, Office of Research of Development, Health Services Research & Development. References American Psychiatric Association. Diagnostic and statistical manual of mental disorders (DSM-IV-TR). Washington, D.C.: American Psychiatric Association; 2000. Blake DD, Weathers FW, Nagy LM, Kaloupek DG, Gustman FD, Charney DS, et al. The development of a clinician-administered PTSD scale. Journal of Traumatic Stress 1995;8:75e90. Blake DD, Weathers FW, Nagy LM, Kaloupek DG, Klauminzer G, Charney DS, et al. A clinician rating scale for assessing current and lifetime PTSD: the CAPS-1. Behavior Therapist 1990;13:187e8. Breslau N, Davis GC, Andreski P, Peterson E. Traumatic events and posttraumatic stress disorders in an urban population of young adults. Archives of General Psychiatry 1991;48:216e22. Breslau N, Kessler R, Chilcoat HD, Schultz LR, Davis GC, Andreski P. Trauma and posttraumatic stress disorder in the community. Archives of General Psychiatry 1998;55:626e32. Carroll EM, Rueger DB, Foy DW, Donahoe CP. Vietnam combat veterans with posttraumatic stress disorder: analysis of marital and cohabitation adjustment. Journal of Abnormal Psychology 1985;94:329e37. Cohen J. Statistical power analysis for the behavioral sciences. 2nd ed. Hillsdale, NJ: Lawrence Earlbaum Associates; 1988. Davidson JRT, Hughes D, Blazer D, George LK. Posttraumatic stress disorder in the community: an epidemiological study. Psychological Medicine 1991;21:1e19. Dohrenwend BP, Turner JB, Turse NA, Adams BG, Koenen KC, Marshall R. The psychological risks of Vietnam for U.S. veterans: a revisit with new data and methods. Science 2006;313:979e82. Erbes CR, Polusny MA, Arbisi PA. Post-traumatic stress disorder and symptoms in National Guard soldiers following combat deployment, under review. First MB, Spitzer RL, Gibbon M, Williams JBW. Structured clinical interview for DSM-IV-TR axis I disorders, research version, non-patient edition. New York: Biometrics Research, New York State Psychiatric Institute; 2002. Grieger TA, Cozza SJ, Ursano RJ, Engel CC, Hoge C, Martinez E, et al. Posttraumatic stress disorder and depression in battle-injured soldiers. America Journal of Psychiatry 2006;163:1777e83. Hoge CW, Auchterlonie JL, Milliken CS. Mental health problems, use of mental health services, and attrition from military service after returning from deployment to Iraq or Afghanistan. Journal of the American Medical Association 2006;295(9):1023e32. Hoge CW, Castro CA, Messer SC, McGurk D, Cotting DI, Koffman RL. Combat duty in Iraq and Afghanistan, mental health problems, and barriers to care. New England Journal of Medicine 2004;351(1):13e22. Jacobson IG, Ryan MAK, Hooper TI, Smith TC, Amoroso PJ, Boyko EJ, et al. Alcohol use and alcohol-related problems before and after military combat deployment. Journal of the American Medical Association 2008;300(6):663e75. Jordan BK, Marmar CR, Fairbank JA, Schlenger WE, Kulka RA, Hough RL, et al. Problems in families of male Vietnam veterans with posttraumatic stress disorder. Journal of Consulting and Clinical Psychology 1992;60:916e26. Jordan BK, Schlenger WE, Hough R, Kulka RA, Weiss D, Fairbank JA, et al. Lifetime and current prevalence of specific psychiatric disorders among Vietnam veterans and controls. Archives of General Psychiatry 1991;48:207e15. Kang HK, Natelson BH, Mahan CM, Lee KY, Murphy FM. Post-traumatic stress disorder and chronic fatigue syndrome-like illness among Gulf War veterans: a population-based survey of 30,000 veterans. American Journal of Epidemiology 2003;157:141e8. Kessler RC. Posttraumatic stress disorder: the burden to the individual and the society. Journal of Clinical Psychiatry 2000;61:4e21. Kessler RC, Frank RG. The impact of psychiatric disorders on work loss days. Psychological Medicine 1997;27:861e73. Kessler RC, McGonagle KA, Zhao S, Nelson CB, Hughes M, Eshleman S, et al. Lifetime and 12-month prevalence of DSM-III-R psychiatric disorders in the United States. Archives of General Psychiatry 1994;51:8e19.
Kessler RC, Sonnega A, Bromet E, Hughes M, Nelson CB. Posttraumatic stress disorder in the National Comorbidity Survey. Archives of General Psychiatry 1995;52:1048e60. King LA, King DW, Vogt DS, Knight JA, Samper RE. Deployment Risk and Resilience Inventory: a collection of measures for studying deployment-related experiences of military personnel and veterans. Military Psychology 2006;18:89e120. Kulka RA, Schlenger WE, Fairbank JA, Hough RL, Jordan BK, Marmar CR, et al. Trauma and the Vietnam War generation: report of findings from the National Vietnam Veterans Readjustment Study. New York: Brunner/Mazel; 1990. Lowe B, Spitzer RL, Grafe K, Kroenke K, Quenter A, Zipfel S, et al. Comparative validity of three screening questionnaires for DSM-IV depressive disorders and physicians’ diagnosis. Journal of Affective Disorders 2004;78(2):131e40. Milliken CS, Auchterlonie JL, Hoge CW. Longitudinal assessment of mental health problems among active and reserve component soldiers returning from the Iraq war. Journal of the American Medical Association 2007;298:2141e8. Narrow WE, Rae DS, Robins LN, Regier DA. Revised prevalence estimates of mental disorders in the United States. Archives of General Psychiatry 2002;59:115e23. Olfson M, Fireman B, Weissman MM, Leon AC, Sheehan DV, Kathol RG, et al. Mental disorders and disability among patients in a primary care group practice. American Journal of Psychiatry 1997;154:1734e40. Ormel J, Von Korff M, Ustun B, Pini S, Korten A, Oldehinkel T. Common mental disorders and disability across cultures: results from the WHO collaborative study on psychological problems in general health care. Journal of the American Medical Association 1994;272:1741e8. Prigerson HG, Maciejewski PK, Rosenheck RA. Population attributable fractions of psychiatric disorders and behavioral outcomes associated with combat exposures among US men. American Journal of Public Health 2002;92:59e63. Regier DA, Myers JK, Kramer M, Robins LN, Blazer DG, Hough RL, et al. The NIMH Epidemiologic Catchment Area program: historical context, major objectives, and study population characteristics. Archives of General Psychiatry 1984;51:8e19. Riddle JR, Smith TC, Smith B, Corbeil TE, Engel CC, Wells TS, et al. Millennium cohort: the 2001e2003 baseline prevalence of mental disorders in the U.S. military. Journal of Clinical Epidemiology 2007;60:192e201. Savoca E, Rosenheck R. The civilian labor market experiences of Vietnam-era veterans: the influence of psychiatric disorders. Journal of Mental Health Policy and Economics 2000;3:199e207. Seal KH, Bertenthal D, Miner CR, Sen S, Marmar C. Bringing the war back home: mental health disorders among 103,788 US veterans returning from Iraq and Afghanistan seen at Department of Veterans Affairs facilities. Archives of Internal Medicine 2007;167(5):476e82. Stein MB, Walker JR, Hazen AL, Forde DR. Full and partial posttraumatic stress disorder: findings from a community survey. American Journal of Psychiatry 1997;154(8):1114e9. Tanielian T, Jaycox LH, editors. Invisible wounds of war: psychological and cognitive injuries, their consequences, and services to assist recovery. Santa Monica, CA: Rand Corporation, http://www.rand.org/pubs/monographs/MG720/; 2008 [accessed 10.03.10]. Terhakopian A, Sinaii N, Engel CC, Schnurr PP, Hoge CW. Estimating population prevalence of posttraumatic stress disorder: an example using the PTSD Checklist. Journal of Traumatic Stress 2008;21(3):290e300. The Iowa Persian Gulf Study Group. Self-reported illness and health status among Gulf War veterans: a population-based study. Journal of the American Medical Association 1997;277:238e45. Turner JB, Turse NA, Dohrenwend BP. Circumstances of service and gender differences in war-related PTSD: findings from the National Vietnam Veterans Readjustment Study. Journal of Traumatic Stress 2007;20:643e9. Weissman MM. SAS-SR: social adjustment scale e self-report. Toronto, Ontario: MHS, Inc.; 1999. Wilcove GL, Schewerin MJ, Wolosin DG. An exploratory model of quality of life in the U.S. Navy. Military Psychology 2003;15:133e52. Zatzick DF, Marmar CR, Weiss DS, Browner W, Metzler TJ, Golding JM, et al. Posttraumatic stress disorders and functioning and quality of life outcomes in a nationally representative sample of male Vietnam veterans. American Journal of Psychiatry 1997;154:1690e5.
Contents lists available at ScienceDirect
Journal of Psychiatric Research journal homepage: www.elsevier.com/locate/psychires
Psychiatric diagnoses, comorbidity, and functioning in National Guard troops deployed to Iraqq Shannon M. Kehle a, b, c, Madhavi K. Reddy b, d, Amanda G. Ferrier-Auerbach b, c, Christopher R. Erbes b, c, Paul A. Arbisi b, c, Melissa A. Polusny a, b, c, * a
Center for Chronic Disease Outcomes Research, Minneapolis, MN, USA Minneapolis VA Medical Center, Minneapolis, MN, USA University of Minnesota Medical School, Minneapolis, MN, USA d Alpert Medical School of Brown University, Providence, RI, USA b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 18 January 2010 Received in revised form 3 May 2010 Accepted 7 May 2010
Objective: Over 1.8 million troops have been deployed to Iraq (OIF) and Afghanistan. Estimates of mental health problems postdeployment have been based on screening instruments; no studies have examined the postdeployment mental health of troops returning from OIF using structured diagnostic interviews. The goal of the current study is to (a) report on rates of mental health diagnoses and comorbidity in soldiers after deployment to OIF using clinical interviews, and (b) examine the relationship between mental health diagnoses and overall functioning and quality of life. Method: Participants were 348 National Guard soldiers drawn from the Readiness and Resilience in National Guard Soldiers (RINGS) study, a longitudinal study of mental health after deployment to OIF from March 2006 to July 2007. Participants completed clinical interviews, including the Clinician Administered PTSD Scale and the Structured Clinical Interview for the DSM-IV, and self-report measures of social adjustment and quality of life 6e12 months following deployment. Results: Most participants did not meet criteria for a mental health diagnosis. Non-PTSD anxiety disorders and depressive disorders were the most common. Mental health diagnoses were associated with poorer functioning and quality of life. PTSD had the strongest relationship with social functioning and quality of life. For those with PTSD, comorbid diagnoses were not associated with an incremental decrease in functioning or quality of life. Conclusions: The findings highlight the significant rate and burden of mental health disorders among this population and suggest that while PTSD is relatively uncommon, it is a particularly deleterious disorder. Published by Elsevier Ltd.
Keywords: Posttraumatic stress disorder (PTSD) Trauma Military Psychiatric diagnosis Quality of life
In recent years there have been increasing concerns regarding the mental health of American soldiers returning from the current wars in Afghanistan (OEF) and Iraq (OIF). Early data suggest high rates of posttraumatic stress disorder (PTSD), depression, and alcohol problems among OEF/OIF soldiers (Hoge et al., 2004, 2006; Jacobson et al., 2008; Seal et al., 2007). To date, most reports of OEF/ OIF postdeployment mental health diagnoses involve rates of probable diagnoses based on the use of self-report measures (Grieger et al., 2006; Hoge et al., 2004, 2006). Using such methodology, estimated rates in returned OEF/OIF military personnel have been reported at up to 25% for PTSD, 13% for depression, and
q This research has not been previously published or presented in any form. * Corresponding author. Minneapolis VA Medical Center (116A9), One Veterans Drive, Minneapolis, MN 55417, USA. Tel.: þ1 (612) 725 2000x3965; fax: þ1 (612) 727 5633. E-mail address: [email protected] (M.A. Polusny). 0022-3956/$ e see front matter Published by Elsevier Ltd. doi:10.1016/j.jpsychires.2010.05.013
12% for alcohol-related disorders (Jacobson et al., 2008; Milliken et al., 2007). The RAND Corporation recently conducted a large epidemiological study of nearly 2000 OEF/OIF soldiers and estimated rates of both PTSD and major depression to be 14% (Tanielian and Jaycox, 2008). While useful because of their ease of administration, self-report assessment tools often result in inaccurate diagnoses and overestimates of illness (Lowe et al., 2004; Terhakopian et al., 2008). Structured clinical interviews, while time intensive, are widely considered to be the most accurate way of diagnosing mental health conditions. We have previously explored rates of postdeployment PTSD in our sample and found that 7% of the troops met criteria using the Clinician Administered PTSD Scale (CAPS; Blake et al., 1995; Erbes et al., under review). To our knowledge, no study has examined the rate of other mental health diagnoses or comorbidity, as assessed by structured clinical interviews, in military personnel who have recently returned from OEF/OIF. Thus, the goal of this paper is to provide the first known report of rates of
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mental health disorders and comorbidities, as diagnosed by structured clinical interviews, in a sample of U.S. National Guard troops who have recently returned from OIF. Additionally, this paper will report on how mental health diagnoses impact the social functioning of these troops. Research conducted with veterans of previous wars has shown that postdeployment mental health disorders are associated with impairments in functioning, decreased quality of life, increased health care costs, and significant financial burdens (The Iowa Persian Gulf Study Group, 1997; Jordan et al., 1991; Kang et al., 2003; Prigerson et al., 2002). PTSD alone is associated with an estimated $3 billion dollars of lost productivity per year, an average 3.6 days of work lost per month, a lowered likelihood of veterans working for pay, and a negative impact on veterans’ wages (Kessler, 2000; Savoca and Rosenheck, 2000). In regards to OEF/OIF, the two-year cost of postdeployment PTSD and major depression is estimated to be between $4.0 and $6.2 billion dollars (Tanielian and Jaycox, 2008). Further, rates of comorbidity among individuals with PTSD have been estimated to be as high as 99% (Kulka et al., 1990) and previous studies have shown the negative impact of PTSD is even greater when another mental health diagnosis is present (Kessler and Frank, 1997). In line with previous research, we expected that soldiers who report a mental health diagnosis will report greater negative impact on their functioning, and that comorbid mental health diagnoses will have a cumulative negative impact on the soldiers’ functioning. 1. Materials and methods The National Guard command and the institutional review boards of the University of Minnesota Medical School, Minneapolis Veteran’s Affairs Medical Center, and Department of Defense approved the study protocol. The investigation was conducted in accordance with the latest version of the Declaration of Helsinki and written informed consent was obtained from participants prior to study enrollment and interview administration. 1.1. Participants and procedures The study sample was drawn from the Readiness and Resilience in National Guard Soldiers (RINGS) Study, a longitudinal investigation of risk and resilience factors predictive of postdeployment mental health in troops deployed to OIF. Soldiers from a National Guard Brigade Combat Team (BCT) were surveyed one month prior to a 16-month deployment to Iraq and again 3 months following return from deployment. As part of the postdeployment survey, a variety of psychological and deployment-related factors, including quality of life and social adjustment, were assessed using standard mailed survey methodology. All participants were also invited to complete a postdeployment diagnostic interview. Interviews were conducted between 6 and 12 months following troops’ return from Iraq. Participants were compensated $130 for completing the interview. Fig. 1 details participation rates. Participants were originally contacted approximately one month prior to deployment to OIF while completing a six-month mobilization training. Over the course of approximately 2½ weeks, soldiers were invited through unit announcements and flyers to attend a group briefing session held by investigators. Ultimately, 522 of the approximately 2600 individuals in the total brigade completed the predeployment survey. Those who participated predeployment were demographically similar to the larger brigade (Table 1). Of the 522 soldiers who participated predeployment, 424 participants (81%) completed the follow-up survey. Postdeployment responders and non-responders did not differ on gender, ethnicity, or self-reported predeployment
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distress. The responders were more likely to be officers (responders ¼ 11%; non-responders ¼ 4%), c2 (1, N ¼ 522) ¼ 4.43, p < 0.05, married (responders ¼ 49%; non-responders ¼ 31%), c2 (1, N ¼ 522) ¼ 10.65, p < 0.001, and older (responder M ¼ 29.9, SD ¼ 8.8; non-responder M ¼ 25.6, SD ¼ 6.9), t(520) ¼ 4.46, p < 0.001, than the non-responders. Eighty-two percent (n ¼ 348) of postdeployment survey responders completed a diagnostic interview. Seven participants completed an interview but not a follow-up survey and were excluded from current analyses. There were no differences between soldiers who completed or did not complete the interview on age, ethnicity, marital status, enlisted status, self-reported distress, social adjustment, or quality of life. Soldiers completing interviews were more likely to report some college education (c2 ¼ 12.96, p < 0.001). Of those completing interviews, 248 soldiers (71%) were interviewed in-person and 100 soldiers (29%) were interviewed via telephone. There were no differences between those interviewed in-person or by phone on demographics (age, ethnicity, marital status, level of education), postdeployment PTSD or depressive symptomology, number of diagnoses, quality of life, or social adjustment. Female soldiers were more likely to participate inperson than by telephone (c2 ¼ 9.49, p ¼ 0.002). 1.2. Measures The Clinician Administered PTSD Scale (CAPS; Blake et al., 1995), considered to be the “gold standard” of PTSD diagnosis, consists of 30-items, and corresponds to the Diagnostic and Statistical Manual of Mental Disorders 4th Edition (DSM-IV-TR; American Psychiatric Association, 2000) criteria for PTSD. Using original CAPS scoring criteria (Blake et al., 1990), PTSD was diagnosed for participants who experienced a traumatic event (criteria A1), reported at least one reexperiencing symptom, three avoidance symptoms, and two hyperarousal symptoms each at a frequency rating of at least 1 and an intensity rating of at least 2, and reported and significant impairment or distress. Subthreshold PTSD was diagnosed for participants who experienced a traumatic event (criteria A1), reported at least one avoidance, one reexperiencing, and one hyperarousal symptoms at a frequency rating of at least 1 and an intensity rating of at least 2, and reported significant impairment or distress (Stein et al., 1997). Additional Axis I disorders were diagnosed with the SCID-I/NP (Non Patient-Edition) Research Version interview (First et al., 2002). The following modules were administered: Overview, Mood Episodes, Psychotic Disorders, Mood Disorders, Substance Use Disorders, Anxiety Disorders (with exception of PTSD questions), and Somatoform Disorders. Selfreport survey data analyzed for the present report were collected by two instruments: the Social Adjustment Scale-Self-Report (SASSR; Weissman, 1999) and Navy Quality of Life Survey (NQOLS; Wilcove et al., 2003). The SAS-SR contains 54-items which assess individual’s functioning in 6 areas: work, social and leisure activities, relationships with extended family, role as a marital partner, parental role, and role within the family unit including economic functioning perceptions. Each item is rated on a five point Likert scale, with higher scores indicating greater impairment. A domainbased approach for assessing soldiers’ quality of life was adapted from the NQOLS. Domains assessed include leisure and recreation, friends and friendship, relationship with relatives, marriage/intimate relationships, relationships with children (if applicable), standard of living, and overall satisfaction with life experiences. Each item is rated on a seven point Likert scale, with higher scores indicating greater satisfaction. We also used the “combat experiences” subscale of the Deployment Risk and Resilience Inventory to assess the presence or absence of a range of combat experiences (King et al., 2006).
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1/34 BCT (N = 2600)
Predeployment Survey (n = 522) Postdeployment Survey Non-Responders (n = 98) Postdeployment Survey (n = 424)
n=7
Interview Non-Completers (n = 76)
Clinical Interviews (n = 355)
In-Person Interviews (n = 248)
Telephone Interviews (n = 100)
Fig. 1. Flow of subjects through data collection.
1.3. Interviewer training and reliability
1.4. Data analysis
Interviews were conducted by a team of eight doctoral level graduate students who completed extensive training and ongoing clinical supervision. Training included a day-long didactic lecture, viewing of administration training tapes, and the completion of “check-out” interviews. To ensure quality of the interviews and prevent drift, refresher training was held for all interviews after approximately three months. All interviewers participated in weekly supervision provided by the investigators at which time interviews were reviewed, and consensus diagnoses were established. All interviews were digitally recorded for reliability purposes. Ten percent of interviews were reviewed and independently rated by a second interviewer. Inter-rater reliabilities for individual diagnoses from the SCID ranged from 0.56 to 1.0. Across all diagnostic categories, inter-rater reliability for the SCID was moderate to good (kappa ¼ 0.67). Reliability for the CAPS was also evaluated across symptom ratings, yielding an interclass correlations coefficient of 0.88.
Pearson chi-square tests were used to examine differences in diagnosis by gender and age category. Logistic regressions were conducted to examine the relationship between each of the diagnostic groups in Table 2 and associated social functioning and quality of life. The comparison group for each of the regressions was the no diagnosis group. With the exception of the no diagnosis group, diagnostic groups were not mutually exclusive because participants could have had more than one diagnosis. Odds ratios (OR), 95% confidence intervals (CI), and p-values are reported for each of the logistic regression comparisons. All continuously distributed variables were converted to z-scores prior to entry into the regression models. Thus, the OR represents the factor by which the odds of having a specific disorder changes in conjunction with a standard deviation difference in the independent variable (e.g. total social functioning). Cohen’s d effect sizes were also calculated for each comparison. The effect sizes can be interpreted using Cohen’s definition of small (0.2), medium (0.5), and large (0.8) effects (Cohen, 1988).
S.M. Kehle et al. / Journal of Psychiatric Research 45 (2011) 126e132 Table 1 Demographic characteristics of interview participants, overall readiness and Resilience in National Guard Soldiers (RINGS) cohort at baseline, and the Brigade Combat Team population. Demographic characteristic
Overall cohort at baseline (n ¼ 522)
Panel participants at follow-up (n ¼ 348)
Brigade Combat Team population (n ¼ 2573)
Sex Male, No. (%)a Female, No. (%)
462 (88) 60 (12)
304 (87) 44 (13)
2339 (91) 234 (9)
Age, mean (SD), y 18e29 years, No. (%) 30þ years, No. (%)
29.1 (8.6) 313 (60) 209 (40)
31.3 (9.5) 170 (49) 172 (51)
1672 (65) 901 (35)
484 (93)
325 (93)
2407 (95)
37 (7)
23 (7)
134 (5)
Rank Enlisted, No. (%) Officer, No. (%)
471 (90) 51 (10)
303 (87) 44 (13)
2301 (90) 270 (10)
Marital status Married, No. (%) Not married, No. (%)
237 (45) 285 (55)
173 (48) 163 (52)
1006 (40) 1515 (60)
Race/ethnicity White, non-Hispanic, No. (%) Non-white, No. (%)
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OEF/OIF. Troops reported substantial exposure to combat and other potentially traumatic war-related events. A large majority of soldiers (91%) reported participating in combat missions or patrols, 94% reported that they or a member of their unit received incoming small arms fire, 55% were attacked by terrorists or civilians, and 22% thought they killed someone in combat. Ten percent of the sample reported being wounded or injured during deployment. 2.2. Rates of postdeployment psychiatric diagnoses
b
a Percentages reported are the proportion of individuals within each demographic subgroup who reported the outcome. b Mean age for the brigade was not available.
Rates of psychiatric comorbidity were calculated for the entire panel, for participants with a diagnosis of PTSD, and for participants with a diagnosis of either PTSD or subthreshold PTSD. For the entire panel, we conducted one-way analysis of covariance (ANCOVA) to examine the association between total number of diagnoses and overall social functioning and quality of life. We then conducted a second ANCOVA to examine the relationship between having no diagnosis, one diagnosis, or two or more diagnoses and overall social functioning and quality of life. Next, using only those with either PTSD or subthreshold PTSD, we again conducted an ANCOVA to examine the association between number of diagnoses and overall social functioning and quality of life. Finally, using only those with PTSD or subthreshold PTSD, we conducted an ANCOVA to examine the association between having a comorbidity (yes/no) and total social adjustment and overall quality of life. Due to a response bias within our sample, we controlled for marital status, education level, age, and enlisted status in the regressions and ANCOVAs. 2. Results 2.1. Sample characteristics and deployment experiences Interview completers were 87% male, 93% Caucasian, 50% married, 87% enlisted rank, with a mean age of 31.30 (SD ¼ 9.5) years (Table 1). Four percent of the sample had a previous deployment to
Table 2 displays rates of postdeployment psychiatric disorders. A majority (62%) of the sample did not meet criteria for a current psychiatric disorder at the time of assessment. Depressive disorders were the most common diagnoses; major depressive disorder was the most frequent diagnosis in that category (n ¼ 41). Non-PTSD anxiety disorders (other anxiety) and alcohol use disorders were also relatively common. The most frequent disorders in the other anxiety category were anxiety disorder not otherwise specified (NOS; n ¼ 20), social anxiety disorder (n ¼ 11), and generalized anxiety disorder (n ¼ 9). Of those who met criteria for an alcohol use disorder, 73% were diagnosed with dependence. As we have previously reported, 7% of the sample met criteria for PTSD (Erbes et al., under review). When those with subthreshold PTSD were included, the sample prevalence increased to 15%. Pain disorder, somatization disorder NOS, and psychotic disorder NOS were each diagnosed in one participant; these disorders were not included in the analyses due to their low prevalence in the sample. Women were more likely than men (52% vs 36%) to have a psychiatric diagnosis, c2 ¼ 4.40, p ¼ 0.04. Specifically, female soldiers were more frequently diagnosed with PTSD (14% vs 6%; c2 ¼ 4.03, p ¼ 0.04), depressive disorders (27% vs 13%; c2 ¼ 6.41, p ¼ 0.01), and non-PTSD anxiety disorders (25% vs 12%; c2 ¼ 6.10, p ¼ 0.01). Age was not significantly associated with the presence of any diagnosis. 2.3. Functioning and quality of life associated with psychiatric diagnoses Table 3 displays the association between psychiatric diagnoses and overall functioning and quality of life among the panel of OIF deployed troops. Drug use disorder was eliminated from these analyses due the small number of cases. Only participants in an intimate relationship (n ¼ 157) were included in the marriage/ intimate relationship analyses, while only those with children (n ¼ 123) were included in the analyses related to parenting. Having a diagnosis of PTSD (M ¼ 2.19, SD ¼ 0.39), subthreshold PTSD (M ¼ 2.17, SD ¼ 0.56), depressive disorder (M ¼ 2.14, SD ¼ 0.48), non-PTSD anxiety disorder (M ¼ 2.00, SD ¼ 0.41), or alcohol use disorder (M ¼ 1.98, SD ¼ 1.20) was associated with lowered social functioning when compared with those without
Table 2 Rates of psychiatric diagnoses among National Guard soldiers approximately six months following OIF deployment. PTSD
Subthreshold PTSD
Depressive disorders
Other anxiety
Alcohol use disorders
Drug use disorders
Total n (%)a
23/348 (7)
30/348 (9)
51/348 (15)
46/348 (13)
45/348 (13)
4/348 (1)
216/348(62)
Gender Male Female
17/304 (6) 6/44 (14)
25/304 (8) 5/44 (11)
39/304 (13) 12/44 (27)
35/304 (12) 11/44 (25)
38/304 (13) 7/44 (16)
3/304 (1) 1/44 (2)
195/304 (64) 21/44 (48)
Age 18e29 30e39 40e49 50e59
14/170 6/110 3/48 0/14
20/170 6/110 3/48 0/14
25/170 16/110 7/48 3/14
18/170 17/110 7/48 3/14
23/170 15/110 6/48 0/14
1/170 3/110 0/48 0/14
105/170 67/110 32/48 9/14
(8) (6) (6) (0)
(12) (6) (6) (0)
(15) (15) (15) (21)
Abbreviations: PTSD, posttraumatic stress disorder. a Rows do not sum because participants can have more than one diagnosis.
(11) (16) (15) (21)
(14) (14) (13) (0)
(1) (3) (0) (0)
No diagnosis
(62) (61) (67) (64)
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Table 3 Self-reported functioning and quality of life associated with psychiatric diagnoses among National Guard soldiers PTSDa
Subthreshold PTSD
Depressive disorders
Other anxiety
Alcohol use disorders
Any diagnosis
2.76** (1.92e3.99) 0.47** (0.34e0.65)
2.19** (1.53e3.15) 0.50** (0.35e0.70)
2.12** (1.45e3.10) 0.59 (0.43e0.81)**
2.16** (1.67e2.80) 0.53** (0.41e0.67)
b
Adjusted odds ratios (95% confidence intervals) Total SAS-SR 3.03** (1.83e5.00) 2.58** (1.71e3.88) Total NQOLS 0.43** (0.28e0.66) 0.44** (0.31e0.64)
Abbreviations: PTSD, posttraumatic stress disorder; SAS-SR, social adjustment scale e self-report; NQOLS, Navy quality of life scale. *p < 0.05. **p < 0.01. a Reference group for all comparisons was no diagnosis. b Adjusted for age, marital status, education level, and enlisted status.
a diagnosis (M ¼ 1.72, SD ¼ 0.35). In regards to PTSD, after adjusting for age, marital status, enlisted status, and educational level, the odds of having PTSD increased three-fold for each standard deviation increase in impairment on the total social functioning score (Table 3). Impairments in social and leisure activities, extended family relationships, and family role functioning were significantly associated with all diagnostic categories Impairment in selfreported functioning as a marital/intimate partner was associated with all diagnoses except PTSD and subthreshold PTSD. Parental role functioning was not associated with any diagnoses. Overall quality of life was negatively associated with having a diagnosis of PTSD (M ¼ 4.35, SD ¼ 1.04), subthreshold PTSD (M ¼ 4.44, SD ¼ 1.26), depressive disorder (M ¼ 4.63, SD ¼ 1.09), non-PTSD anxiety disorder (M ¼ 4.81, SD ¼ 0.99), or alcohol use disorder (M ¼ 4.90, SD ¼ 1.20) when compared with those without a diagnosis (M ¼ 5.48, SD ¼ 0.94). In regards to PTSD, for each standard deviation change in satisfaction with quality of life (representing increased satisfaction), the odds of having PTSD decreased by a little over one-half (Table 3). Decreased quality of life in leisure and recreational activities, relationships with relatives, and standard of living were significantly related to all diagnostic categories. Decreased quality of life related to friends and friendship was associated with all diagnoses except alcohol use disorder. The subdomain of marriage/intimate relationships was significantly, negatively related to all diagnostic categories but PTSD and non-PTSD anxiety disorders. Finally, decreased satisfaction with relationships with children was only associated with PTSD and the depressive disorders. An examination of effect sizes revealed that PTSD had the largest association with disruptions in social functioning and quality of life. PTSD (d ¼ 1.27 and d ¼ 1.14 respectively), subthreshold PTSD (d ¼ 0.96 and d ¼ 0.94), and depressive disorders (d ¼ 0.99 and d ¼ 0.84) all had large associations with overall social functioning and quality of life. The effect sizes for non-PTSD anxiety (d ¼ 0.73 and d ¼ 0.69) and alcohol use disorders (d ¼ 0.29 and d ¼ 0.54) were in the small to medium range. 2.4. Rates of psychiatric comorbidity Twenty-three percent of the sample had only one diagnosis, 10% had two diagnoses, 3% had three diagnoses, and 2% had four or more diagnoses. Among participants with PTSD, the average number of diagnoses was 1.74 (SD ¼ 1.36) with a range of zero to five. Eighty-seven percent of those with PTSD had at least one additional diagnosis; 44% had one, 17% had two, 13% had three, and 13% had four or more comorbid diagnoses. Table 4 shows rates of specific comorbid diagnoses among participants with a diagnosis of PTSD and a diagnosis of either PTSD or subthreshold PTSD. 2.5. Impact of psychiatric comorbidity on functioning and quality of life For the entire panel, a one-way ANCOVA showed that number of diagnoses was associated with impairments in overall social
functioning, F(6, 337) ¼ 9.97, p < 0.001, and quality of life, F(6, 337) ¼ 8.79, p < 0.001. When we categorized participants into three groups (no diagnosis, one diagnosis, two or more diagnoses), we again found that number of diagnoses was associated with impairments in both overall social functioning F(2, 341) ¼ 28.95, p < 0.001 and quality of life F(2, 341) ¼ 25.49, p < 0.001. Posthoc tests (Least Significant Difference) showed that each group differed significantly from each other (p 0.002). For those with a diagnosis of PTSD or subthreshold PTSD, a one-way ANCOVA showed that additional diagnoses were not related to further impairments in total functioning, F(5, 37) ¼ 1.66, p ¼ 0.22, or overall quality of life, F(5, 37) ¼ 0.24, p ¼ 0.64. Similarly, among individuals with PTSD or subthreshold PTSD, there were no significant differences in social functioning, F(1, 41) ¼ 0.002, p ¼ 0.96, or quality of life, F(1, 41) ¼ 0.44, p ¼ 0.44, between those with and without comorbid disorders.
3. Discussion We found that a majority of National Guard soldiers recently returned from a combat deployment to Iraq did not meet criteria for a mental health disorder. However, overall rates were higher in this panel than in epidemiological studies of community dwelling residents, in which overall past-year prevalence among adults has ranged from 20 to 30% (Kessler et al., 1994; Narrow et al., 2002; Reiger et al., 1984). Rates of disorders were also substantially higher in this postdeployment sample than in an epidemiological study of a general, non-OIF deployed, military cohort (Riddle et al., 2007). The soldiers had slightly higher rates than community and non-deployed military samples across all diagnoses, with the exception of drug use disorders. Not surprisingly, the greatest elevation was in PTSD, which was double the population estimate of 3.6% (Kessler et al., 1994; Narrow et al., 2002). However, the rate of PTSD in our panel was similar to what has been observed in other trauma exposed populations (Breslau et al., 1998), and to recent estimates of PTSD among Vietnam veterans. While the National Vietnam Veterans’ Readjustment Study (NVVRS) originally estimated that 15.2% of Vietnam veterans met criteria for PTSD approximately 10 years after the end of the war (Kulka et al., 1990), reanalyses of those data resulted in an estimated prevalence of 9.7% (Dohrenwend et al., 2006). While rates of PTSD in our sample were lower than in other studies of OIF soldiers that relied on self-report measures, self-report measures of depression and alcohol use disorders yielded rates similar to those in our panel (Hoge et al., 2004; Jacobson et al., 2008; Milliken et al., 2007). Finally, comorbidity was common. More than 85% of soldiers with a diagnosis of PTSD had at least one additional mental health diagnosis, with depressive disorders being the most common. These findings are similar to PTSD comorbidity rates in both the community and among Vietnam veterans, which have estimated lifetime comorbidity between 60 and 99% (Breslau et al., 1991; Davidson et al., 1991; Kessler et al., 1995; Kulka et al., 1990). Over one-half of female soldiers had a mental health diagnosis and female soldiers were significantly more likely to have a mental health diagnosis than male soldiers. Specifically, in our panel,
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Table 4 Rates of comorbidity among National Guard soldiers with a diagnosis of PTSD.
PTSD diagnosis n (%)a PTSD or subthreshold PTSD diagnosis n (%)a
Depressive disorders
Other anxiety
Alcohol use disorders
Drug use disorders
No comorbid diagnosis
16/23 (70) 27/53 (51)
8/23 (35) 15/53 (28)
5/23 (22) 10/53 (19)
0/23 (0) 1/53 (2)
3/23 (13) 10/53 (19)
Abbreviations. PTSD, posttraumatic stress disorder. a Rows do not sum because participants can have more than one comorbid diagnosis.
women were diagnosed with PTSD, depressive disorders, and non-PTSD anxiety disorders at twice the rate of men. These discrepancies are in line with epidemiological studies (both general population and military); however, the overall rate of mental health disorders among female soldiers is substantially higher than in females in the general population (Kessler et al., 1994). Further, these data reflect a shift in the roles and outcomes of deployed female soldiers, as data from NVVRS revealed that female Vietnam veterans had PTSD at one-half the rate of their male counterparts (Turner et al., 2007). Given this finding, the impact of combat deployments on female soldiers’ mental health will be an important area of future study. Soldiers with a mental health diagnosis reported significant impairments in both social functioning and quality of life. All of the diagnostic categories were related to substantial impairments and decreased quality of life. However, PTSD was associated with the greatest impairments. Among Vietnam veterans, PTSD has been associated with impaired social and familial role functioning, poor health status, diminished well-being, and disruptions in work functioning (Carroll et al., 1985; Jordan et al., 1992; Zatzick et al., 1997). Our data suggest that the presence of PTSD is associated with similar problems among OIF soldiers as early as six months postdeployment. Contrary to our hypotheses, psychiatric comorbidity among soldiers with PTSD was not related to further impairments in social functioning or quality of life. However, having more than one diagnosis was related to higher levels of impairment in the full panel. Previous epidemiological and clinic-based studies have found that having more than one psychiatric diagnosis is associated with a greater disturbance in functioning and quality of life (Kessler and Frank, 1997; Olfson et al., 1997; Ormel et al., 1994). While it is important to view the results regarding PTSD as preliminary due to the small number of participants with PTSD, it may be that among this population, PTSD is particularly debilitating and those with PTSD are already experiencing such large disruptions that a “floor effect” may be occurring, in which comorbid diagnoses do not further reduce quality of life and social functioning. This study has a number of strengths, including the use of goldstandard clinical interviews and a large non-treatment seeking population. However, participants were self-selected. Thus, while the panel demographics are similar to that of the overall brigade, this was not an epidemiological study and results may not generalize either to other National Guard units or the larger military population. Further, although our analyses suggest few differences between responders and non-responders and we attempted to control for response bias in the analyses, the findings may have been influenced by either postdeployment survey or interview response biases. Our panel also had a very small number of soldiers with previous OEF/OIF deployments. The relationship between multiple deployments, psychiatric diagnoses, and functioning is an important area of future study. Also, a number of our diagnostic conditions had few participants, thus, we may have been underpowered to find differences between groups, particularly for analyses examining intimate relationships and parenting. Conclusions regarding functioning and quality of life are based on self-report and must be considered preliminary. It is possible that the selfreport items measured a general sense of well-being, rather than
specific domains of functioning. As such, the findings require further objective validation (e.g. collateral reports; objective work performance data) in a larger sample. Finally, it is important to note that we do not have predeployment diagnostic data, thus, we cannot conclude that the disorders are the result of deployment to a combat zone. Rather, the study highlights the overall postdeployment mental health burden of soldiers deployed to OIF. This study is the first to provide diagnostic data for a community sample of OIF soldiers. The data highlight the significant rate and burden of mental health disorders among this population. Further, while PTSD appears to be particularly deleterious, it is also relatively uncommon. Thus, the findings highlight the importance of successfully identifying and treating a range of mental health problems, not only PTSD, in returning soldiers. If untreated, these disorders may have devastating effects, both for the soldier and for society. Contributors Shannon Kehle participated in study conceptualization and design, analysis and interpretation of data, drafting and revision of the manuscript, and statistical analysis. Madhavi Reddy participated in acquisition of data, drafting and revision of the manuscript, and administrative support. Amanda Ferrier-Auerbach participated in study conception and design, drafting and revision of the manuscript, and administrative support. Christopher Erbes participated in study conceptualization and design, acquisition of data, supervision, revision of the manuscript, and obtaining funding. Paul Arbisi participated in study conceptualization and design, acquisition of data, supervision, revision of the manuscript, administrative support, and obtaining funding. Melissa Polusny participated in study conceptualization and design, acquisition of data, supervision, analysis and interpretation of data, revision of the manuscript, and obtaining funding. Role of funding source This research was supported by the Minneapolis VA Medical Center Research Service and grants to Melissa A. Polusny, PhD, from Minnesota Medical Foundation (Grant #3662-9227-06) and Department of Defense Congressionally Directed Medical Research Program (CDMRP) (W81XWH-07-2-003) and a grant to Christopher R. Erbes, PhD, from the Department of Veterans Affairs Health Service Research and Development program (RRP 08-385). None of the sponsors had any role in the following: design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript. Conflict of interest All authors declare that they have no conflicts of interest. Acknowledgements The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of Veterans Affairs, Department of the Army, or the Department of Defense. This material is supported in part by the Department of
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Veterans Affairs, Veterans Health Administration, Office of Research of Development, Health Services Research & Development. References American Psychiatric Association. Diagnostic and statistical manual of mental disorders (DSM-IV-TR). Washington, D.C.: American Psychiatric Association; 2000. Blake DD, Weathers FW, Nagy LM, Kaloupek DG, Gustman FD, Charney DS, et al. The development of a clinician-administered PTSD scale. Journal of Traumatic Stress 1995;8:75e90. Blake DD, Weathers FW, Nagy LM, Kaloupek DG, Klauminzer G, Charney DS, et al. A clinician rating scale for assessing current and lifetime PTSD: the CAPS-1. Behavior Therapist 1990;13:187e8. Breslau N, Davis GC, Andreski P, Peterson E. Traumatic events and posttraumatic stress disorders in an urban population of young adults. Archives of General Psychiatry 1991;48:216e22. Breslau N, Kessler R, Chilcoat HD, Schultz LR, Davis GC, Andreski P. Trauma and posttraumatic stress disorder in the community. Archives of General Psychiatry 1998;55:626e32. Carroll EM, Rueger DB, Foy DW, Donahoe CP. Vietnam combat veterans with posttraumatic stress disorder: analysis of marital and cohabitation adjustment. Journal of Abnormal Psychology 1985;94:329e37. Cohen J. Statistical power analysis for the behavioral sciences. 2nd ed. Hillsdale, NJ: Lawrence Earlbaum Associates; 1988. Davidson JRT, Hughes D, Blazer D, George LK. Posttraumatic stress disorder in the community: an epidemiological study. Psychological Medicine 1991;21:1e19. Dohrenwend BP, Turner JB, Turse NA, Adams BG, Koenen KC, Marshall R. The psychological risks of Vietnam for U.S. veterans: a revisit with new data and methods. Science 2006;313:979e82. Erbes CR, Polusny MA, Arbisi PA. Post-traumatic stress disorder and symptoms in National Guard soldiers following combat deployment, under review. First MB, Spitzer RL, Gibbon M, Williams JBW. Structured clinical interview for DSM-IV-TR axis I disorders, research version, non-patient edition. New York: Biometrics Research, New York State Psychiatric Institute; 2002. Grieger TA, Cozza SJ, Ursano RJ, Engel CC, Hoge C, Martinez E, et al. Posttraumatic stress disorder and depression in battle-injured soldiers. America Journal of Psychiatry 2006;163:1777e83. Hoge CW, Auchterlonie JL, Milliken CS. Mental health problems, use of mental health services, and attrition from military service after returning from deployment to Iraq or Afghanistan. Journal of the American Medical Association 2006;295(9):1023e32. Hoge CW, Castro CA, Messer SC, McGurk D, Cotting DI, Koffman RL. Combat duty in Iraq and Afghanistan, mental health problems, and barriers to care. New England Journal of Medicine 2004;351(1):13e22. Jacobson IG, Ryan MAK, Hooper TI, Smith TC, Amoroso PJ, Boyko EJ, et al. Alcohol use and alcohol-related problems before and after military combat deployment. Journal of the American Medical Association 2008;300(6):663e75. Jordan BK, Marmar CR, Fairbank JA, Schlenger WE, Kulka RA, Hough RL, et al. Problems in families of male Vietnam veterans with posttraumatic stress disorder. Journal of Consulting and Clinical Psychology 1992;60:916e26. Jordan BK, Schlenger WE, Hough R, Kulka RA, Weiss D, Fairbank JA, et al. Lifetime and current prevalence of specific psychiatric disorders among Vietnam veterans and controls. Archives of General Psychiatry 1991;48:207e15. Kang HK, Natelson BH, Mahan CM, Lee KY, Murphy FM. Post-traumatic stress disorder and chronic fatigue syndrome-like illness among Gulf War veterans: a population-based survey of 30,000 veterans. American Journal of Epidemiology 2003;157:141e8. Kessler RC. Posttraumatic stress disorder: the burden to the individual and the society. Journal of Clinical Psychiatry 2000;61:4e21. Kessler RC, Frank RG. The impact of psychiatric disorders on work loss days. Psychological Medicine 1997;27:861e73. Kessler RC, McGonagle KA, Zhao S, Nelson CB, Hughes M, Eshleman S, et al. Lifetime and 12-month prevalence of DSM-III-R psychiatric disorders in the United States. Archives of General Psychiatry 1994;51:8e19.
Kessler RC, Sonnega A, Bromet E, Hughes M, Nelson CB. Posttraumatic stress disorder in the National Comorbidity Survey. Archives of General Psychiatry 1995;52:1048e60. King LA, King DW, Vogt DS, Knight JA, Samper RE. Deployment Risk and Resilience Inventory: a collection of measures for studying deployment-related experiences of military personnel and veterans. Military Psychology 2006;18:89e120. Kulka RA, Schlenger WE, Fairbank JA, Hough RL, Jordan BK, Marmar CR, et al. Trauma and the Vietnam War generation: report of findings from the National Vietnam Veterans Readjustment Study. New York: Brunner/Mazel; 1990. Lowe B, Spitzer RL, Grafe K, Kroenke K, Quenter A, Zipfel S, et al. Comparative validity of three screening questionnaires for DSM-IV depressive disorders and physicians’ diagnosis. Journal of Affective Disorders 2004;78(2):131e40. Milliken CS, Auchterlonie JL, Hoge CW. Longitudinal assessment of mental health problems among active and reserve component soldiers returning from the Iraq war. Journal of the American Medical Association 2007;298:2141e8. Narrow WE, Rae DS, Robins LN, Regier DA. Revised prevalence estimates of mental disorders in the United States. Archives of General Psychiatry 2002;59:115e23. Olfson M, Fireman B, Weissman MM, Leon AC, Sheehan DV, Kathol RG, et al. Mental disorders and disability among patients in a primary care group practice. American Journal of Psychiatry 1997;154:1734e40. Ormel J, Von Korff M, Ustun B, Pini S, Korten A, Oldehinkel T. Common mental disorders and disability across cultures: results from the WHO collaborative study on psychological problems in general health care. Journal of the American Medical Association 1994;272:1741e8. Prigerson HG, Maciejewski PK, Rosenheck RA. Population attributable fractions of psychiatric disorders and behavioral outcomes associated with combat exposures among US men. American Journal of Public Health 2002;92:59e63. Regier DA, Myers JK, Kramer M, Robins LN, Blazer DG, Hough RL, et al. The NIMH Epidemiologic Catchment Area program: historical context, major objectives, and study population characteristics. Archives of General Psychiatry 1984;51:8e19. Riddle JR, Smith TC, Smith B, Corbeil TE, Engel CC, Wells TS, et al. Millennium cohort: the 2001e2003 baseline prevalence of mental disorders in the U.S. military. Journal of Clinical Epidemiology 2007;60:192e201. Savoca E, Rosenheck R. The civilian labor market experiences of Vietnam-era veterans: the influence of psychiatric disorders. Journal of Mental Health Policy and Economics 2000;3:199e207. Seal KH, Bertenthal D, Miner CR, Sen S, Marmar C. Bringing the war back home: mental health disorders among 103,788 US veterans returning from Iraq and Afghanistan seen at Department of Veterans Affairs facilities. Archives of Internal Medicine 2007;167(5):476e82. Stein MB, Walker JR, Hazen AL, Forde DR. Full and partial posttraumatic stress disorder: findings from a community survey. American Journal of Psychiatry 1997;154(8):1114e9. Tanielian T, Jaycox LH, editors. Invisible wounds of war: psychological and cognitive injuries, their consequences, and services to assist recovery. Santa Monica, CA: Rand Corporation, http://www.rand.org/pubs/monographs/MG720/; 2008 [accessed 10.03.10]. Terhakopian A, Sinaii N, Engel CC, Schnurr PP, Hoge CW. Estimating population prevalence of posttraumatic stress disorder: an example using the PTSD Checklist. Journal of Traumatic Stress 2008;21(3):290e300. The Iowa Persian Gulf Study Group. Self-reported illness and health status among Gulf War veterans: a population-based study. Journal of the American Medical Association 1997;277:238e45. Turner JB, Turse NA, Dohrenwend BP. Circumstances of service and gender differences in war-related PTSD: findings from the National Vietnam Veterans Readjustment Study. Journal of Traumatic Stress 2007;20:643e9. Weissman MM. SAS-SR: social adjustment scale e self-report. Toronto, Ontario: MHS, Inc.; 1999. Wilcove GL, Schewerin MJ, Wolosin DG. An exploratory model of quality of life in the U.S. Navy. Military Psychology 2003;15:133e52. Zatzick DF, Marmar CR, Weiss DS, Browner W, Metzler TJ, Golding JM, et al. Posttraumatic stress disorders and functioning and quality of life outcomes in a nationally representative sample of male Vietnam veterans. American Journal of Psychiatry 1997;154:1690e5.