MILITARY MEDICINE, 169, 11:896, 2004 Lifetime nd 12-Month Prevlence of Psychitric Disorders in 8,169 Mle Vietnm Wr Er Veterns Gurntor: Seth A. Eisen, MD Contributors: Seth A. Eisen, MD* ; Kristin H. Griffith, MA ; Hong Xin, PhD ; Jeffrey F. Scherrer, MA ; Irene D. Fischer, MA ; Sunnt Chntrujikpong, MD ; Joyce Hunter, MSN ; Willim R. True, PhD ; Michel J. Lyons, PhD #; Ming T. Tsung, MD** Objective: This study reports the prevlence of psychitric disorders mong ntionlly distributed smple of Vietnm Er veterns ssessed using stndrdized psychitric interviewing methods. Methods: In 1992, the Ntionl Institute of Mentl Helth Dignostic Interview Schedule ws dministered by telephone to 8,169 middle-ged mles who served in the militry during the Vietnm er (1965 1975). Results: Approximtely 72% of respondents reported lifetime history nd 36% reported 12-month history of t lest one psychitric disorder. The most prevlent psychitric disorders included lcohol buse nd/or dependence (54% lifetime, 17% 12 month), nicotine dependence (48% lifetime, 22% 12 month), nd posttrumtic stress disorder (10% lifetime, 4.5% 12 month). Conclusions: Becuse of possible prticiption bis, these results likely represent conservtive estimtes of psychitric disorder prevlences mong the more thn eight million Vietnm Er veterns nd reinforces the mjor public helth chllenge of preventing, identifying, nd treting psychitric illness in Americn veterns. Introduction tudies of the prevlence nd ssocitions of psychitric disorders in popultions cn provide the bsis for developing S hypotheses bout the etiology of the disorders nd ssist in formulting priorities for prevention nd tretment. Severl psychitric epidemiologicl studies published during the lst 20 yers used lrge smple sizes nd relible dignostic methods nd smpling techniques to ssess the prevlence of psychitric disorders, the extent of comorbidity, nd demogrphic correltes of psychitric illnesses in different popultions. 1 5 To dte, the primry sources of informtion on the prevlence of psychitric disorders in the United Sttes re the Epidemiologicl Ctchment Are Study (ECA) 5 nd the Ntionl Comorbidity Study (NCS). 2 In the ECA, more thn 20,000 respondents in five communities were dministered structured interview to determine the prevlence of psychitric disorders s defined *Reserch nd Medicl Service nd Reserch Service, Deprtment of Vetern Affirs Medicl Center, St. Louis, MO 63106. Division of Generl Medicl Sciences, Deprtments of Internl Medicine nd Psychitry, Wshington University School of Medicine, St. Louis, MO 63110. Deprtment of Internl Medicine, Wshington University School of Medicine, St. Louis, MO 63110. School of Public Helth, Sint Louis University, St. Louis, MO 63104. Deprtment of Psychology, Boston University, Boston, MA 02215. #Hrvrd Institute of Psychitric Epidemiology nd Genetics, Boston, MA 02115. **Deprtment of Psychitry, Institute of Behviorl Genomics, University of Cliforni, Sn Diego, Sn Diego, CA. Deprtments of Epidemiology nd Psychitry, Hrvrd Institute of Psychitric Epidemiology nd Genetics, Boston, MA 02115. This mnuscript ws received for review in September 2003. The revised mnuscript ws ccepted for publiction in December 2003. primrily by the Dignostic nd Sttisticl Mnul of Mentl Disorders, Third Edition (DSM-III). 6 The NCS dministered the University of Michign-Composite Interntionl Dignostic Interview (UM-CIDI) to representtive U.S. smple of 8,098 respondents to dignose psychitric disorders ccording to Dignostic nd Sttisticl Mnul of Mentl Disorders, Third Edition Revised (DSM-III-R). 7 Two lrge-scle studies hve exmined the prevlence of psychitric disorders mong veterns who served in the militry during the Vietnm Er: the Centers for Disese Control Vietnm Experience Study (VES), multidimensionl psychologicl ssessment on rndom subsmple of 4,462 Vietnm veterns; 8 nd the Ntionl Vietnm Veterns Redjustment Study (NVVRS), which ssessed the prevlence of psychitric disorders in 2,348 Vietnm veterns. 9 11 The present study exmines the prevlence of 20 DSM-III-R psychitric disorders mong 8,169 middle-ged mle members of the Vietnm Er Twin (VET) Registry, ntionl dtbse of twin pirs, both of which were in service during the Vietnm Er. In 1992, this ntionlly distributed smple, identified without regrd to psychitric sttus or other helth chrcteristics, ws dministered the Ntionl Institute of Mentl Helth Dignostic Interview Schedule Version 3, Revised (DIS-III-R) 12 to obtin dt on the prevlence of DSM-III-R criteri psychitric disorders. Becuse the NVVRS nd VES used different smpling techniques thn the present study, used DSM-III (rther thn DSM-III-R) criteri for most dignoses, nd did not report posttrumtic stress disorder (PTSD) bsed on DSM criteri, our nlyses will contribute to the existing literture on vetern mentl helth. Comprisons to the NVVRS nd VES will be discussed. Mterils nd Methods Smple The VET Registry ws developed from Deprtment of Defense computer file of pproximtely 5.5 million Vietnm Er veterns born between 1939 nd 1957 who served on ctive militry duty during the Vietnm Wr (My 1965 to August 1975). Using n lgorithm tht mtched dtbse entries for sme lst nme, different first nme, sme dte of birth, nd similr socil security numbers, totl of 7,369 twin pirs were identified. A complete description of the registry s construction nd method of zygosity determintion is vilble elsewhere. 13 15 The bsis for the present report is structured psychitric interview tht ws conducted in 1992. All VET Registry twin pirs in which t lest one member responded to survey conducted in 1987 nd his cotwin hd not refused to prticipte in future studies nd ws not known to be decesed were eligible 896
Prevlence of Psychitric Disorders in Vietnm Veterns for the 1992 interview. Of these 10,300 eligible individuls (5,129 twin pirs nd 42 singletons), 47 were subsequently determined to be decesed or significntly incpcitted. Of the remining 10,253 individuls, 8,169 were interviewed (3,516 twin pirs nd 1,137 singletons). Psychitric Assessment nd Dignosis In 1992, respondents were interviewed vi telephone by trined nd experienced interviewers using computerized version of the DIS-III-R. 16 The DIS-III-R is reserch dignostic interview designed to be dministered by trined ly interviewers to ssess psychitric disorders ccording to DSM-III-R criteri. 7 Before the interview, potentil prticipnts were sent letter tht explined the purpose of the study. One to 2 weeks lter, n interviewer phoned the subject, reviewed the reserch project, nd solicited verbl informed consent to prticipte. The DIS-III-R is the most widely used ssessment instrument for psychitric dignosis in community smples. It is designed to elicit psychitric dignostic elements including symptoms, symptom severity, frequency, distribution over time, nd whether or not symptoms re due to physicl illness, use of drugs or lcohol, or the presence of nother psychitric disorder. The following DSM-III-R dignoses were ssessed: lcohol buse nd dependence, nicotine (dependence only), mjor depressive episode, mjor depression, bipolr disorder, mnic episode, dysthymi, pnic disorder, generlized nxiety disorder, PTSD, ntisocil personlity disorder (ASPD), conduct disorder, pthologicl gmbling, nd illicit drug buse nd dependence (mphetmine, cnnbis, cocine, opioids, phencyclidine, lysergic cid diethylmide (LSD), nd sedtives). Both lifetime nd 12-month prevlence of psychitric disorders were clculted. Lifetime prevlence is the proportion of the smple who hd ever experienced the disorder, while 12-month prevlence is the proportion who experienced the disorder t some time during the 12 months before the interview. Becuse of unvilbility of dt, 12-month prevlence rtes were not computed for conduct disorder nd pthologicl gmbling. Relibility To ssess relibility, subset of 146 prticipnts were reinterviewed by n interviewer other thn the one who performed the originl interview. The men time between interviews ws 466 dys (SD, 50.5; rnge, 357 601). Kpp sttistics for test-retest relibility 17 of lifetime prevlence rnged from 0.54 to 0.60 for ffective disorders, from 0.25 to 0.32 for nxiety disorders, from 0.26 to 0.76 for substnce use disorders, nd from 0.34 to 0.41 for other disorders (ASPD, conduct disorder, nd pthologicl gmbling). The sttistic for ny disorder (excluding nicotine dependence) ws 0.78. Overll, the test-retest relibility for most of the DSM-III-R psychitric dignoses ws stisfctory, especilly considering the low prevlence of mny of the disorders nd the men durtion between interviews of nerly 1.3 yers. Relibility ws poor ( 0.40) for pnic disorder, generl nxiety disorder, PTSD, ny nxiety disorder, nd pthologicl gmbling. Dt Anlysis We included ll 8,169 veterns (twin pirs nd singletons combined) in our nlyses. We creted computer lgorithms to derive the lifetime nd 12-month dignostic vribles for ll 20 psychitric disorders, the proportion of the smple with comorbid lifetime nd 12-month disorders, nd the ge-djusted odds rtios (ORs) for the likelihood of lifetime nd 12-month psychitric disorders s function of demogrphic vrible ctegories. Additionlly, summry lgorithms were derived for three ctegories of psychitric disorders (Tble I: ny ffective disorder, ny nxiety disorder, nd ny illicit drug buse nd/or dependence) nd for three summry vribles for ll of the psychitric disorders (ny disorder, ny disorder except lcohol buse nd/or dependence, nd ny disorder except lcohol buse nd/or dependence nd nicotine dependence). Becuse 12- month estimtes of the prevlence of conduct disorder nd pthologicl gmbling could not be clculted for this smple, we did not include these two disorders in the three summry estimtes for lifetime nd 12-month prevlence of ny psychitric disorder. Becuse dt derived from twin siblings re not independent observtions, proportions, ORs, nd 95% confidence intervls (CI) for lifetime nd 12-month prevlence nd comorbidity estimtes were clculted using Stt (Version 5). 18 Approprite estimtes of 95% CI of the smple with prticulr psychitric disorders, djusted for the clustered nture of the twin dt, were generted bsed on Huber s robust vrince estimtor. We identified the twin pir s the primry smpling unit, thereby correcting for the nonindependence of the dt. Age-djusted ORs for the likelihood of prticulr psychitric disorders by ctegory of individul demogrphic vribles were lso computed using STATA. Results 897 In 1992, the men ge of the 8,169 respondents ws 42.0 yers (SD, 2.8; rnge, 34 53 yers). Most were Cucsin (93.5%), 6.1% were Africn Americn, 1% were Hispnic, nd 0.3% were other. Most (95.6%) were employed t the time of the interview. In 1992, 75.9% of respondents were mrried, 16.4% were widowed, seprted, or divorced, nd 7.7% hd never been mrried. The distribution of nnul household income in 1987 (the lst yer for which dt were vilble) ws 20.8% of respondents erned less thn $20,000, 46.7% erned between $20,000 nd $40,000, nd 32.5% erned more thn $40,000 nnully. Eight percent of respondents did not grdute from high school, 92.0% were high school grdutes, 22.0% were college grdutes, nd 10.2% received eduction beyond college degree. Nerly 40% (37.8%) of respondents hd been sttioned in Vietnm t some time during their militry service. Prevlence of Psychitric Disorders Tble I presents the DSM-III-R psychitric disorder prevlence estimtes (percentges nd 95% CI) of the 20 lifetime nd eighteen 12-month disorders for the 8,169 veterns. Psychitric disorders re presented in five mjor ctegories: ffective disorders (mjor depressive episode, mjor depression, bipolr disorder, mnic episode, nd dysthymi), nxiety disorders (pnic disorder, generlized nxiety disorder, nd PTSD), licit (lcohol buse nd/or dependence, nicotine dependence) nd illicit (mphetmine, cnnbis, cocine, opioid, phencyclidine/lsd, sed-
898 Prevlence of Psychitric Disorders in Vietnm Veterns TABLE I LIFETIME AND 12-MONTH PREVALENCE OF DIAGNOSTIC STATISTICAL MANUAL, 3RD REVISION, PSYCHIATRIC DISORDERS IN 8,169 VIETNAM WAR ERA VETERANS Lifetime (N 8,169) 12 Month (N 8,169) Psychitric Disorders % 95% CI % 95% CI Affective disorders Mjor depressive episode 9.7 9.0 10.3 3.3 2.9 3.7 Mjor depression 9.1 8.4 9.7 3.3 2.9 3.7 Bipolr disorder 0.6 0.4 0.8 0.1 0.0 0.1 Mnic episode 0.8 0.6 1.0 0.0 0.0 0.1 Dysthymi 2.3 2.0 2.7 0.7 0.5 0.9 Any ffective disorder 10.5 9.8 11.1 3.5 3.1 4.0 Anxiety disorders Pnic disorder 1.8 1.5 2.0 0.8 0.6 1.0 Generlized nxiety disorder 1.5 1.2 1.7 1.2 1.0 1.4 PTSD 10.1 9.4 10.7 4.6 4.1 5.0 Any nxiety disorder 11.9 11.1 12.6 5.7 5.2 6.2 Licit substnce use disorders Alcohol buse only 18.9 18.1 19.8 4.0 3.6 4.4 Alcohol dependence only 35.7 34.5 36.9 13.3 12.5 14.1 Nicotine dependence 47.6 46.4 48.9 23.3 22.3 24.3 Illicit substnce use disorders Amphetmine buse nd/or dependence 2.7 2.3 3.1 0.1 0.1 0.2 Cnnbis buse nd/or dependence 7.1 6.5 7.7 1.0 0.8 1.2 Cocine buse nd/or dependence 2.7 2.3 3.0 0.3 0.2 0.4 Opioid buse nd/or dependence 1.3 1.0 1.5 0.1 0.0 0.1 PCP/LSD buse nd/or dependence 1.1 0.8 1.3 0.1 0.0 0.1 Sedtive buse nd/or dependence 1.4 1.2 1.7 0.1 0.0 0.2 Any illicit drug buse nd/or dependence 10.2 9.5 11.0 1.3 1.1 1.6 Other disorders Antisocil personlity disorder 2.8 2.4 3.2 1.5 1.2 1.8 Conduct disorder 8.1 7.5 8.8 Pthologicl gmbling 2.3 1.9 2.7 Any disorder 71.9 70.9 73.1 37.7 36.6 38.9 Any disorder except lcohol buse nd/or dependence 56.8 55.6 58.0 28.8 27.8 29.9 Any disorder except lcohol buse nd/or dependence nd nicotine dependence 28.0 26.9 29.0 9.6 8.9 10.3 This informtion is not vilble/ws not collected for the prticulr disorder. tive buse nd/or dependence) substnce use disorders, nd other disorders (ASPD, conduct disorder, nd pthologicl gmbling). Of the disorders ssessed, the prevlence estimtes of lcohol buse nd/or dependence nd nicotine dependence were prticulrly high for lifetime (54.6% nd 47.6%, respectively) nd 12-month (17.3% nd 23.3%, respectively) periods. Lifetime prevlence ws similr (between 10.2% nd 11.9%) for the ctegories of ny ffective disorder, ny nxiety disorder, nd ny illicit drug buse nd/or dependence. For 12-month prevlence ctegories, ny nxiety disorder ws the highest (5.7%), wheres the prevlence of ny ffective disorder nd ny illicit drug buse nd/or dependence were much lower (3.5% nd 1.3%, respectively). Tble I demonstrtes tht bout 7 of every 10 respondents reported lifetime history of t lest one psychitric disorder, while more thn 1 of every 3 respondents reported 12-month history of t lest one disorder. If lcohol buse nd/or dependence nd nicotine dependence re not included in the ctegory ny disorder, then bout 3 in 10 respondents reported lifetime history of t lest one psychitric disorder nd bout 1 in 10 respondents hd 12-month history of t lest one psychitric disorder. The prevlence of most of the psychitric disorders in the pst 12 months ws low. Twelve-month prevlence estimtes greter thn 1.5% were observed only for nicotine dependence, lcohol buse nd/or dependence, PTSD, mjor depressive episode, nd mjor depression. Psychitric Comorbidity Mny respondents met criteri for more thn one psychitric disorder. As shown in Tble II, 12.1% of the respondents met criteri for two lifetime disorders (not including nicotine dependence) nd 11.2% hd three or more lifetime disorders. Approximtely 3% hd two 12-month disorders nd 1.6% hd three or more 12-month disorders. Of those with t lest one lifetime disorder, 19.9% hd two lifetime disorders nd 18.4% hd three or more lifetime disorders. Of those with t lest one 12-month psychitric disorder, 13.6% hd two 12-month disorders, while 6.9% hd three or more. Assocition of Demogrphic Chrcteristics nd Psychitric Disorders Age-djusted OR of selected DSM-III-R lifetime psychitric disorders by rce, mritl sttus, eduction, nnul household
Prevlence of Psychitric Disorders in Vietnm Veterns 899 TABLE II DISTRIBUTION OF LIFETIME AND 12-MONTH COMORBID DISORDERS IN 8,169 VIETNAM WAR ERA VETERANS (INCLUDES ALL DISORDERS EXCEPT NICOTINE DEPENDENCE) Psychitric Disorders Lifetime Disorders (N 8,169) 12-Month Disorders (N 8,169) Of Those Who Hd t Lest One Psychitric Disorder Comorbid Lifetime Disorders (N 4,997) Comorbid 12-Month Disorders (N 1,914) No. of Disorders % 95% CI % 95% CI % 95% CI % 95% CI 0 38.9 37.7 40.0 76.6 75.6 77.6 1 37.8 36.7 38.9 18.6 17.7 19.5 61.8 60.4 63.2 79.5 77.6 81.3 2 12.1 11.4 12.9 3.2 2.8 3.6 19.9 18.7 21.0 13.6 12.1 15.2 3 11.2 10.5 12.0 1.6 1.3 1.9 18.4 17.2 19.5 6.9 5.7 8.1 Percentge (37.8/[37.8 12.1 11.2]) 100 61.8%. income, nd present employment re reported for five psychitric disorders (lcohol buse nd/or dependence, PTSD, mjor depression, ny illicit drug buse nd/or dependence, nicotine dependence) in Tble III. For ll five psychitric disorders, the risk of hving the disorder in one s lifetime ws significntly higher for those who were widowed, seprted, or divorced (vs. mrried), who erned less thn $20,000/yer (vs. those erning $40,000/yer or more), nd who were unemployed vs. employed. Being never mrried (vs. mrried) ws sttisticlly significntly ssocited with n incresed likelihood of meeting lifetime criteri for mjor depression (OR, 1.46; 95% CI, 1.10, 1.94) nd ny illicit drug buse nd/or dependence (OR, 1.74; 95% CI, 1.35, 2.25). Respondents who were never mrried were significntly less likely to meet lifetime criteri for nicotine dependence compred with those who were mrried (OR, 0.78; 95% CI, 0.66, 0.93). Compred with those with more thn high school eduction, those with less thn high school eduction were sttisticlly significntly more likely to meet criteri for lcohol buse nd/or dependence (OR, 1.68; 95% CI, 1.28, 2.21), PTSD (OR, 1.67; 95% CI, 1.17, 2.38), nd nicotine dependence (OR, 2.85; 95% CI, 2.18, 3.73). Africn Americns were sttisticlly significntly less likely thn Cucsins to meet the criteri for lcohol buse nd/or dependence (OR, 0.61; 95% CI, 0.50, 0.74) nd for nicotine dependence (OR, 0.59; 95% CI, 0.48, 0.72). Age-djusted ORs for the ssocitions of demogrphic fctors with the sme five psychitric disorders for the previous 12 months were lso clculted (Tble IV). Sttisticl significnce ws found between ech of the five disorders nd mritl sttus (widowed/seprted/divorced vs. mrried), low nnul household income, nd unemployment. Those who were never mrried (vs. mrried) were sttisticlly significntly more likely to meet the criteri for lcohol buse nd/or dependence (OR, 1.39; 95% CI, 1.12, 1.72), mjor depression (OR, 1.80; 95% CI, 1.16, 2.79), nd ny illicit drug buse nd/or dependence (OR, 3.21; 95% CI, 1.86, 5.54). TABLE III AGE-ADJUSTED DEMOGRAPHIC RISK FACTORS FOR LIFETIME PSYCHIATRIC DISORDERS IN 8,169 VIETNAM WAR ERA VETERANS Alcohol Abuse or PTSD Mjor Depression Any Illicit Drug Abuse or Nicotine OR 95% CI OR 95% CI OR 95% CI OR 95% CI OR 95% CI Rce Cucsin 1.0 1.0 1.0 1.0 1.0 Africn Americn 0.61 c 0.50 0.74 1.09 0.81 1.46 0.94 0.67 1.31 1.32 0.98 1.78 0.59 c 0.48 0.72 Mritl sttus Mrried 1.0 1.0 1.0 1.0 1.0 Never mrried 0.98 0.82 1.16 0.91 0.68 1.21 1.46 c 1.10 1.94 1.74 c 1.35 2.25 0.78 c 0.66 0.93 Widowed/seprted/divorced 1.65 c 1.46 1.87 1.51 c 1.26 1.80 2.97 c 2.52 3.50 1.94 c 1.61 2.33 1.47 c 1.31 1.66 Eduction b High school grdute 1.0 1.0 1.0 1.0 1.0 High school grdute 1.10 0.98 1.23 0.91 0.76 1.09 0.85 0.70 1.02 0.87 0.73 1.05 1.39 c 1.25 1.54 High school grdute 1.68 c 1.28 2.21 1.67 c 1.17 2.38 1.39 0.96 2.01 1.31 0.90 1.92 2.85 c 2.18 3.73 Annul household income b $40,000 or more 1.0 1.0 1.0 1.0 $20,000 40,000 0.96 0.87 1.07 1.34 c 1.11 1.62 1.20 1.00 1.44 1.38 c 1.13 1.68 1.13 c 1.02 1.26 $0 20,000 1.19 c 1.03 1.38 2.21 c 1.77 2.75 1.63 c 1.30 2.04 2.18 c 1.74 2.74 1.50 c 1.30 1.73 Presently employed Yes 1.0 1.0 1.0 1.0 1.0 No 1.51 c 1.21 1.89 2.01 c 1.50 2.70 2.05 c 1.53 2.75 2.15 c 1.60 2.90 1.41 c 1.13 1.75 Demogrphic dt derived from militry records. b Demogrphic dt derived from 1987 survey. c Significntly different from comprison (p 0.05).
900 Prevlence of Psychitric Disorders in Vietnm Veterns TABLE IV AGE-ADJUSTED DEMOGRAPHIC RISK FACTORS FOR 12-MONTH PSYCHIATRIC DISORDERS IN 8,169 VIETNAM WAR ERA VETERANS Alcohol Abuse or PTSD Mjor Depression Any Illicit Drug Abuse or Nicotine OR 95% CI OR 95% CI OR 95% CI OR 95% CI OR 95% CI Rce Cucsin 1.0 1.0 1.0 1.0 1.0 Africn Americn 1.06 0.86 1.31 1.02 0.65 1.60 1.00 0.58 1.73 1.36 0.65 2.84 0.80 0.63 1.02 Mritl sttus Mrried 1.0 1.0 1.0 1.0 1.0 Never mrried 1.39 c 1.12 1.72 1.00 0.67 1.51 1.80 c 1.16 2.79 3.21 c 1.86 5.54 1.08 0.88 1.32 Widowed/seprted/divorced 2.33 c 2.02 2.68 1.52 c 1.18 1.96 2.97 c 2.28 3.86 3.30 c 2.17 5.02 1.90 c 1.67 2.16 Eduction b High school grdute 1.0 1.0 1.0 1.0 1.0 High school grdute 1.15 1.00 1.32 0.99 0.76 1.30 0.99 0.72 1.35 1.08 0.66 1.76 1.69 c 1.49 1.92 High school grdute 1.10 0.80 1.53 2.57 c 1.66 3.98 2.27 c 1.34 3.86 1.36 0.56 3.31 2.71 c 2.08 3.52 Annul household income b $40,000 or more 1.0 1.0 1.0 1.0 1.0 $20,000 40,000 1.12 0.97 1.29 1.46 c 1.10 1.94 0.94 0.68 1.29 1.54 0.83 2.87 1.29 c 1.13 1.46 $0 20,000 1.38 c 1.15 1.65 2.53 c 1.83 3.51 1.70 c 1.17 2.45 4.12 c 2.19 7.74 2.08 c 1.77 2.44 Presently employed Yes 1.0 1.0 1.0 1.0 1.0 No 1.79 c 1.40 2.29 2.44 c 1.67 3.56 1.96 c 1.22 3.17 2.63 c 1.39 5.00 1.74 c 1.38 2.19 Demogrphic dt derived from militry records. b Demogrphic dt derived from 1987 survey. c Significntly different from comprison (p 0.05). A lower level of eduction ws sttisticlly significntly ssocited with PTSD (OR, 2.57; 95% CI, 1.66, 3.98), mjor depression (OR, 2.27; 95% CI, 1.34, 3.86), nd nicotine dependence (OR, 2.71; 95% CI, 2.08, 3.52), but ws not sttisticlly significntly ssocited with lcohol buse nd/or dependence or ny illicit drug buse or dependence. There ws no sttisticlly significnt reltionship between rce nd ny of these five psychitric disorders. The ssocition of gretest mgnitude ws for the likelihood of ny illicit drug buse nd/or dependence mong those with low (vs. high) income (OR, 4.12; 95% CI, 2.19, 7.74). After djusting for ge, subjects who hd n nnul income of $20,000 or less were 4.2 times more likely to meet lifetime criteri for ny illicit drug buse nd/or dependence. Discussion This study demonstrtes tht lrge proportion of middleged Americn mles who served in the militry during the Vietnm Er hve been ffected by t lest one psychitric disorder in their lifetime. Of 19 psychitric disorders ssessed (i.e., excluding nicotine dependence), 61.1% of respondents hd lifetime history of t lest one disorder nd 23.4% met the criteri for t lest one disorder in the 12 months before the interview. Even fter excluding lcohol buse nd/or dependence, bout 1 in 4 hd lifetime history nd bout 1 in 10 hd 12-month history of t lest one psychitric disorder. The strengths of this study include the lrge smple size, the ntionl distribution of respondents, the selection of the smple without regrd to psychitric sttus, the stndrdized dt gthering methodology, nd the ssessment of psychitric disorders ccording to DSM-III-R criteri. Our conclusions re likely to be pplicble to ll nonclinicl smples of Vietnm Er mle veterns, becuse twin studies of psychitric illness re generlizble to nontwin popultions. 19 The primry limittion of the study results from the potentil problem of nonresponse bis. Of the 10,300 members of the VET Registry who were trgeted for the 1992 study, 8,169 were interviewed. The remining 2,136 VET Registry members (20.7%) did not prticipte becuse they refused (n 1,990), were ded (n 43), or dministrtive problems prevented us from locting or contcting them (n 98). To ddress the nonresponse bis issue, responders nd nonresponders to the 1992 survey were compred on the following vribles: rce nd eduction t entry into militry service, score on the Armed Forces Qulifiction Test (AFQT, test of ptitude nd intelligence), nd deployment to Vietnm. A greter proportion of Cucsins thn non-cucsins responded (80.1% vs. 70.2%, respectively, p 0.0,001), greter proportion of those who hd some eduction beyond high school thn those who hd no eduction beyond high school responded (86.2% vs. 79.6%, respectively, p 0.0,001), nd individuls with higher AFQT scores were more likely to prticipte (e.g., 83.6% of those whose AFQT score ws in the highest 20% responded vs. 69.6% of those whose AFQT score ws in the lowest 20%, p 0.0,001). Respondents nd nonrespondents were eqully likely to hve been deployed to Vietnm (80.1% of those who served in Vietnm responded vs. 78.9% of those did not serve in Vietnm, p 0.15). Becuse previous reserch suggests n inverse reltionship between the prevlence of psychitric disorders nd sociodemogrphic sttus, 20 it seems likely tht psychitric disorders re more common mong nonresponders to the 1992 survey thn responders. Thus, the prevlence of psychitric disorders observed in this study probbly represent conservtive estimtes of the true prevlence.
Prevlence of Psychitric Disorders in Vietnm Veterns Becuse individuls were required to pss bttery of psychologicl ssessments before induction, individuls with severe disorders, such s schizophreni, were probbly excluded from militry service. This likely resulted in mentlly helthier smple s compred with civilin popultions. 21,22 Lstly, our results re limited to middle-ged men nd my not generlize to women or to older or younger ge cohorts. Prevlence Becuse of differences in smple selection nd dt collection methodology, cution must be used when compring the present study to the NVVRS, VES, ECA, nd NCS studies. For exmple, the NVVRS included Vietnm veterns regrdless of service brnch, enlistment sttus, or number of tours of duty; ssessed psychitric disorders ccording to DSM-III criteri (with the exception of PTSD); conducted fce-to-fce interviews; nd defined current s the previous 6 months. The dignosis of PTSD by the NVVRS ws constructed from responses to the Mississippi Combt-Relted PTSD Scle, the PTSD component of the Structured Clinicl Interview for DSM-III, 20 nd the PTSD Scle of the Minnesot Multiphsic Personlity Inventory. 10,11 The VES limited prticipnts to those who hd t lest 16 weeks of ctive service but only one tour of duty, erned militry occuptionl specilty other thn trinee or duty soldier, nd hd py grde no higher thn E-5 (sergent) t dischrge; used DSM-III criteri, conducted fce-to-fce interviews, nd defined current s the previous month. 8 The ECA smpled the U.S. generl popultion ges 18 yers nd older nd used fce-tofce interviews to ssess prevlence of 1-month, 6-month, 1-yer, nd lifetime DSM-III psychitric disorders. 5,23 The NCS smpled the noninstitutionlized civilin popultion ges 15 to 54, nd used the UM-CIDI in fce-to-fce interviews to ssess the 12-month nd lifetime prevlence of DSM-III-R psychitric disorders. In the present study, lthough veterns were eligible regrdless of the number of tours of duty, n honorble dischrge ws required; we used DSM-III-R criteri for ll dignoses, conducted telephone interviews, nd defined current s the previous 12 months. The lifetime nd current prevlence of lcohol buse nd/or dependence found by our study nd the other studies of Vietnm Er veterns is generlly higher thn tht reported for civilin mle popultions. We found tht 55% of our respondents hd lifetime prevlence of lcohol buse nd/or dependence nd pproximtely 17% hd 12-month history; the NVVRS reported tht 39.2% of veterns hd lifetime prevlence of lcohol buse nd/or dependence nd 11.2% hd 6-month history; 9 nd the VES reported lifetime lcohol buse nd/or dependence estimtes of 50.6% for theter veterns nd 41.8% for nonveterns nd 1-month prevlences of 13.7% for theter nd 9.2% for nontheter veterns. By contrst, the civilin (control) component of the NV- VRS reported lifetime nd 6-month prevlences of lcohol buse nd/or dependence of 25.2% nd 7.0%, respectively; 9 the mle respondents in the NCS between ges 15 nd 54 reported lifetime nd 12-month prevlences of lcohol buse nd/or dependence of 32.6% nd 14.1%, respectively; 2 nd the ECA generted lifetime nd 12-month prevlences of lcohol buse nd/or dependence for men in the generl popultion of 13.8% nd 6.8%, respectively. 5 These results strongly suggest tht lcohol buse nd/or dependence is serious problem mong Vietnm Er veterns nd is more common mong Vietnm Er veterns thn nonveterns. 901 The present study lso suggests tht the prevlence of PTSD is higher mong Vietnm Er veterns thn nonveterns. Ten percent of VET Registry members hd lifetime history of PTSD, nd lmost 5% hd 12-month history of this disorder. Although it is difficult to compre our study findings to published results from other vetern popultions becuse of differences in ssessment methodology, the NVVRS reported 30.9% lifetime prevlence of PTSD for mle theter veterns 10 nd 6-month prevlence of 15.2%, 11 nd the VES reported lifetime prevlence of PTSD of 14.7%. 8 In contrst, only 6% of mle NCS respondents ges 15 to 54 stisfied criteri for hving hd PTSD t some time in their lifetime. 24 The higher prevlence of lifetime nd current PTSD mong Vietnm veterns compred with the generl popultion is not surprising. In ddition, our dt suggest tht the lifetime prevlence of PTSD is higher mong Vietnm theter veterns (15.0%) thn non-theter veterns (6.1%). Approximtely 10% of VET Registry members hd lifetime history of illicit drug buse nd/or dependence nd 1.3% stisfied the 12-month criteri. This pttern is similr to prevlences reported by the NVVRS (5.7% lifetime for theter nd 7.0% for nontheter; 1.8% 6-month for theter nd 1.5% for nontheter) 14 nd VES studies (pproximtely 14% lifetime, 0.4% current). The ECA reported 6.1% lifetime nd 2.0% 6-month prevlence of ny drug buse nd/or dependence. The lifetime nd 12-month prevlences reported by the NCS for its mle respondents ges 15 to 54 were 15% nd 5%, respectively. Approximtely 11% of VET Registry members hd lifetime history of n ffective disorder nd 3.5% hd 12-month history. These results re similr to the civilin cohort in the NCS study 2 in which 14.7% of 15- to 54-yer-old mles hd lifetime history nd 8.5% hd 12-month history. The lifetime nd 12-month prevlences of generlized nxiety disorder we observed, 1.5% nd 1.2%, respectively, re less thn the 3.6% nd 2.0% reported for mle respondents ges 15 to 54 by the NCS study. 2,25 This lower prevlence of generlized nxiety disorder mong Vietnm veterns is unexplined nd hs not been reported by other studies of Vietnm veterns. Comorbidity Although some studies hve indicted tht Vietnm veterns hve higher prevlences of comorbid psychitric disorders by comprison to the generl popultion, 26 our results do not support this. We observed tht mong Vietnm veterns who hd t lest one lifetime psychitric disorder, 38% hd t lest second lifetime disorder other thn nicotine dependence (i.e., 19.9% 18.4% in Tble II), nd mong those with current disorder, more thn 20% hd second current disorder (13.6% 6.9% in Tble II). This comorbid prevlence contrsts with the ECA study, which found tht 60% of those with t lest one lifetime psychitric disorder hd second lifetime disorder, 5 nd the NCS, which found tht 79% of respondents with one lifetime psychitric disorder hd second lifetime disorder. 2 Differences in ssessments nd smple popultions might explin the observed lower prevlence of comorbid disorders mong VET Registry members s compred with the ECA nd NCS studies. First, disorders tht were commonly comorbid in the ECA study, such s somtiztion disorder, schizophreni, gorphobi, nd obsessive-compulsive disorder, were not ssessed in the present study. Hd we ssessed these disorders, the prevlence of psychitric comorbidity my hve been closer
902 Prevlence of Psychitric Disorders in Vietnm Veterns to estimtes from the ECA. Our ssessments were limited to men while the ECA nd NCS studies included women nd men. Women re more likely thn men to hve more thn one psychitric disorder during their lifetime. 2 The ECA nd NCS lso included men nd women s young s 18 yers of ge. These younger subjects re more likely to report more thn one psychitric disorder during their lifetime. 2 In ddition, the helth requirements for militry service would hve excluded those subjects with severe comorbidity (e.g., those with comorbid severe depression nd chronic lcoholism). Lstly, comorbidity in this community smple of veterns is expected to be lower thn tht found in more severely ffected clinicl vetern popultions. Sociodemogrphic Associtions Mritl sttus, employment, nd income were most strongly nd consistently ssocited with psychopthology. Those who were widowed, seprted, or divorced, unemployed, or reported lower nnul incomes hd higher rtes in ll ctegories of lifetime nd current disorders thn those who were mrried or employed or hd higher incomes. Our results re consistent with the ECA study tht found the rtes of lifetime psychitric disorders were high mong subjects who hd been seprted or divorced, subjects who were not working full-time, nd subjects who were working in unskilled jobs. 5 Conclusions The high lifetime nd current prevlence of psychitric disorders mong this ntionlly distributed, nonclinicl smple of mle Vietnm Er veterns reinforces the mjor public helth chllenge of mentl illness mong veterns. More effective methods must be developed to prevent, identify, nd tret psychitric illness, especilly lcohol buse nd dependence nd PTSD in Vietnm Er veterns. Acknowledgments The U.S. Deprtment of Vetern Affirs (DVA) hs provided finncil support for the development nd mintennce of the VET Registry. 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