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Cognitive ability and risk of post-traumatic stress disorder after military deployment: an observational cohort study

  • Lars R. Nissen (a1), Karen-Inge Karstoft (a1), Mia S. Vedtofte (a1), Anni B.S. Nielsen (a1), Merete Osler (a2), Erik L. Mortensen (a3), Gunhild T. Christensen (a2) and Søren B. Andersen (a4)...
Abstract
Background

Studies of the association between pre-deployment cognitive ability and post-deployment post-traumatic stress disorder (PTSD) have shown mixed results.

Aims

To study the inflence of pre-deployment cognitive ability on PTSD symptoms 6–8 months post-deployment in a large population while controlling for pre-deployment education and deployment-related variables.

Method

Study linking prospective pre-deployment conscription board data with post-deployment self-reported data in 9695 Danish Army personnel deployed to different war zones in 1997–2013. The association between pre-deployment cognitive ability and post-deployment PTSD was investigated using repeated-measure logistic regression models. Two models with cognitive ability score as the main exposure variable were created (model 1 and model 2). Model 1 was only adjusted for pre-deployment variables, while model 2 was adjusted for both pre-deployment and deployment-related variables.

Results

When including only variables recorded pre-deployment (cognitive ability score and educational level) and gender (model 1), all variables predicted post-deployment PTSD. When deployment-related variables were added (model 2), this was no longer the case for cognitive ability score. However, when educational level was removed from the model adjusted for deployment-related variables, the association between cognitive ability and post-deployment PTSD became significant.

Conclusions

Pre-deployment lower cognitive ability did not predict post-deployment PTSD independently of educational level after adjustment for deployment-related variables.

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Copyright
This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Corresponding author
Lars R. Nissen, Danish Defence Veteran Centre, Reasearch and Knowledge Centre, Garnisonen 1, 4100 Ringsted, Denmark. E-mail: lrnissen@dadlnet.dk
Footnotes
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Declaration of interest

None.

Footnotes
References
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1 Vogt, D, Smith, BN, King, LA, King, DW, Knight, J, Vasterling, JJ. Deployment Risk and Resilience Inventory-2 (DRRI-2): an updated tool for assessing psychosocial risk and resilience factors among service members and veterans. J Trauma Stress 2013; 26: 710–7.
2 Hoge, CW, Terhakopian, A, Castro, CA, Messer, SC, Engel, CC. Association of posttraumatic stress disorder with somatic symptoms, health care visits, and absenteeism among Iraq war veterans. Am J Psychiatry 2007; 164: 150–3.
3 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. N Engl J Med 2004; 351: 1322.
4 Marmar, C, Schlenger, W, Henn-Haase, C, Qian, M, Purchia, E, Li, M, et al. Course of posttraumatic stress disorder 40 years after the Vietnam war: Findings from the National Vietnam Veterans Longitudinal Study. JAMA Psychiatry 2015; 72: 875–81.
5 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. JAMA 2006; 295: 1023–32.
6 Rona, RJ, Hooper, R, Jones, M, Iversen, AC, Hull, L, Murphy, D, et al. The contribution of prior psychological symptoms and combat exposure to post Iraq deployment mental health in the UK military. J Trauma Stress 2009; 22: 11–9.
7 Rona, RJ, Hooper, R, Jones, M, Hull, L, Browne, T, Horn, O, et al. Mental health screening in armed forces before the Iraq war and prevention of subsequent psychological morbidity: follow-up study. BMJ 2006; 333: 991.
8 Xue, C, Ge, Y, Tang, B, Liu, Y, Kang, P, Wang, M, et al. A meta-analysis of risk factors for combat-related PTSD among military personnel and veterans. PLoS One 2015; 10: e0120270.
9 Brewin, C, Andrews, B, Valentine, J. Meta-analysis of risk factors for posttraumatic stress disorder in trauma-exposed adults. J Consult Clin Psychol 2000; 68: 748–66.
10 Kremen, WS, Koenen, KC, Boake, C, Purcell, S, Eisen, SA, Franz, CE, et al. Pretrauma cognitive ability and risk for posttraumatic stress disorder: a twin study. Arch Gen Psychiatry 2007; 64: 361–8.
11 Thompson, WW, Gottesman, II. Challenging the conclusion that lower preinduction cognitive ability increases risk for combat-related post-traumatic stress disorder in 2,375 combat-exposed, Vietnam War veterans. Mil Med 2008; 173: 576–82.
12 S⊘rensen, HJ, Andersen, SB, Karstoft, K-I, Madsen, T. The influence of pre-deployment cognitive ability on post-traumatic stress disorder symptoms and trajectories: The Danish USPER follow-up study of Afghanistan veterans. J Affect Disord 2016; 196: 148–53.
13 Teasdale, TW. The Danish Draft Board's intelligence test, Borge Priens Prove: psychometric properties and research applications through 50 years. Scand J Psychol 2009; 50: 633–8.
14 Christensen, GT, Molbo, D, Ängquist, LH, Mortensen, EL, Christensen, K, S⊘rensen, TIA, et al. Cohort Profile: The Danish Conscription Database(DCD): a cohort of 728 160 men born from 1939 through 1959. Int J Epidemiol 2015; 44: 432–40.
15 Teasdale, TW, Hartmann, PVW, Pedersen, CH, Bertelsen, M. The reliability and validity of the Danish Draft Board Cognitive Ability Test: B⊘rge Prien's Pr⊘ve. Scand J Psychol 2011; 52: 126–30.
16 Berntsen, D, Johannessen, KB, Thomsen, YD, Bertelsen, M, Hoyle, RH, Rubin, DC. Peace and war: trajectories of posttraumatic stress disorder symptoms before, during, and after military deployment in Afghanistan. Psychol Sci 2012; 23: 1557–65.
17 Weathers, FW, Litz, BT, Herman, DS, Huska, JA, Keane, TM. The PTSD Checklist (PCL): reliability, validity, and diagnostic utility. Paper presented at the Annual Meeting of the International Society for Traumatic Stress Studies, San Antonio, Texas, 1993.
18 Karstoft, K-I, Andersen, SB, Nielsen, ABS. Assessing PTSD in the military: validation of a scale distributed to Danish soldiers after deployment since 1998. Scand J Psychol 2017; 58: 260–8.
19 McFadden, D. Conditional logit analysis of qualitative choice behavior. In Frontiers in Econometrics (ed. Zarembka, P): 105–42. Wiley, 1973.
20 Deary, IJ, Johnson, W. Intelligence and education: causal perceptions drive analytic processes and therefore conclusions. Int J Epidemiol 2010; 39: 1362–9.
21 Urfer-Parnas, A, Lykke Mortensen, E, Saebye, D, Parnas, J. Pre-morbid IQ in mental disorders: a Danish draft-board study of 7486 psychiatric patients. Psychol Med 2010; 40: 547–56.
22 Mikkelsen, SS, Flensborg-Madsen, T, Eliasen, M, Mortensen, EL. A longitudinal cohort study of intelligence and later hospitalisation with mental disorder. Compr Psychiatry 2014; 55: 912–9.
23 Ehlers, A, Clark, DM. A cognitive model of posttraumatic stress disorder. Behav Res Ther 2000; 38: 319–45.
24 Utzon-Frank, N, Breinegaard, N, Bertelsen, M, Borritz, M, Eller, NH, Nordentoft, M, et al. Occurrence of delayed-onset post-traumatic stress disorder: a systematic review and meta-analysis of prospective studies. Scand J Work Environ Health 2014; 40: 215–29.
25 Eekhout, I, Reijnen, A, Vermetten, E, Geuze, E. Post-traumatic stress symptoms 5 years after military deployment to Afghanistan: an observational cohort study. Lancet Psychiatry 2016; 3: 5864.
26 Lee, DJ, Warner, CH, Hoge, CW. Advances and controversies in military posttraumatic stress disorder screening. Curr Psychiatry Rep 2014; 16: 467.
27 Warner, CH, Appenzeller, GN, Parker, JR, Warner, CM, Hoge, CW. Effectiveness of mental health screening and coordination of in-theater care prior to deployment to Iraq: a cohort study. Am J Psychiatry 2011; 168: 378–85.
28 Karstoft, K-I, Statnikov, A, Andersen, SB, Madsen, T, Galatzer-Levy, IR. Early identification of posttraumatic stress following military deployment: application of machine learning methods to a prospective study of Danish soldiers. J Affect Disord 2015; 184: 170–5.
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Cognitive ability and risk of post-traumatic stress disorder after military deployment: an observational cohort study

  • Lars R. Nissen (a1), Karen-Inge Karstoft (a1), Mia S. Vedtofte (a1), Anni B.S. Nielsen (a1), Merete Osler (a2), Erik L. Mortensen (a3), Gunhild T. Christensen (a2) and Søren B. Andersen (a4)...
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