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Social Psychiatry and Psychiatric Epidemiology

Erschienen in:

21.01.2023 | Original Paper

Military service and risk of subsequent drug use disorders among Swedish men

verfasst von: Alexis C. Edwards, Henrik Ohlsson, Peter B. Barr, Jan Sundquist, Kenneth S. Kendler, Kristina Sundquist

Erschienen in: Social Psychiatry and Psychiatric Epidemiology | Ausgabe 7/2023

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Abstract

Purpose

Environmental factors contribute substantially to risk for drug use disorders (DUD). The current study applies multiple methods to empirically test whether military service is associated with subsequent DUD, as previous findings are inconsistent.

Methods

Longitudinal Swedish national registry data on a cohort of male conscripts born 1972–1987 (maximum N = 485,900) were used to test the association between military service and subsequent registration for DUD. Cox proportional hazard models were used in preliminary analyses, followed by three methods that enable causal inference: propensity score models, co-relative models, and instrumental variable analysis.

Results

Across all methods, military service was causally associated with lower risk of DUD. Hazard ratios ranged from HR = 0.43 (95% confidence intervals [CI] 0.37; 0.50) in the instrumental variable analysis to 0.77 (0.75; 0.79) in the multivariate propensity score matching analysis. This effect diminished across time. In the model including a propensity score, HRs remained below 1 across the observation period, while confidence intervals included 1 after ~ 11 years in the co-relative analysis and after ~ 21 years in the instrumental variable analysis.

Conclusions

In this cohort of Swedish men, complementary methods indicate that military service conferred substantial but time-limited protection against subsequent DUD. The observed effect could be due to reduced opportunity for substance use during service, social cohesion experienced during and after service, and/or socioeconomic advantages among veterans. Additional research is necessary to clarify these protective mechanisms and determine how other environmental contexts can provide similar benefits.

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Crowe AV, Howse M, Bell GM, Henry JA (2000) Substance abuse and the kidney. QJM 93(3):147–152. https://doi.org/10.1093/qjmed/93.3.147CrossRefPubMed

Roy DN, Goswami R (2016) Drugs of abuse and addiction: a slippery slope toward liver injury. Chem Biol Interact 255:92–105. https://doi.org/10.1016/j.cbi.2015.09.018CrossRefPubMed

Riezzo I, Fiore C, De Carlo D, Pascale N, Neri M, Turillazzi E, Fineschi V (2012) Side effects of cocaine abuse: multiorgan toxicity and pathological consequences. Curr Med Chem 19(33):5624–5646. https://doi.org/10.2174/092986712803988893CrossRefPubMed

Khalsa JH, Treisman G, McCance-Katz E, Tedaldi E (2008) Medical consequences of drug abuse and co-occurring infections: research at the National Institute on Drug Abuse. Subst Abuse 29(3):5–16. https://doi.org/10.1080/08897070802218661CrossRef

Volkow ND, Li TK (2005) Drugs and alcohol: treating and preventing abuse, addiction and their medical consequences. Pharmacol Ther 108(1):3–17. https://doi.org/10.1016/j.pharmthera.2005.06.021CrossRefPubMed

Davis L, Uezato A, Newell JM, Frazier E (2008) Major depression and comorbid substance use disorders. Curr Opin Psychiatry 21(1):14–18. https://doi.org/10.1097/YCO.0b013e3282f32408CrossRefPubMed

Lai HM, Cleary M, Sitharthan T, Hunt GE (2015) Prevalence of comorbid substance use, anxiety and mood disorders in epidemiological surveys, 1990–2014: a systematic review and meta-analysis. Drug Alcohol Depend 154:1–13. https://doi.org/10.1016/j.drugalcdep.2015.05.031CrossRefPubMed

Luo F, Li M, Florence C (2021) State-level economic costs of opioid use disorder and fatal opioid overdose—United States, 2017. MMWR Morb Mortal Wkly Rep 70:541–546CrossRefPubMedPubMedCentral

Edwards AC, Ohlsson H, Sundquist J, Sundquist K, Kendler KS (2020) Socioeconomic sequelae of drug abuse in a Swedish national cohort. Drug Alcohol Depend 212:107990. https://doi.org/10.1016/j.drugalcdep.2020.107990CrossRefPubMedPubMedCentral

10.

Kreek MJ, Nielsen DA, Butelman ER, LaForge KS (2005) Genetic influences on impulsivity, risk taking, stress responsivity and vulnerability to drug abuse and addiction. Nat Neurosci 8(11):1450–1457. https://doi.org/10.1038/nn1583CrossRefPubMed

11.

Kendler KS, Jacobson KC, Prescott CA, Neale MC (2003) Specificity of genetic and environmental risk factors for use and abuse/dependence of cannabis, cocaine, hallucinogens, sedatives, stimulants, and opiates in male twins. Am J Psychiatry 160(4):687–695. https://doi.org/10.1176/appi.ajp.160.4.687CrossRefPubMed

12.

Maes HH, Neale MC, Ohlsson H, Zahery M, Lichtenstein P, Sundquist K, Sundquist J, Kendler KS (2016) A bivariate genetic analysis of drug abuse ascertained through medical and criminal registries in Swedish twins, siblings and half-siblings. Behav Genet 46(6):735–741. https://doi.org/10.1007/s10519-016-9801-7CrossRefPubMedPubMedCentral

13.

Sundquist J, Sjostedt C, Winkleby M, Li X, Kendler KS, Sundquist K (2016) Neighborhood linking social capital as a predictor of drug abuse: a Swedish national cohort study. Addict Behav 63:37–44. https://doi.org/10.1016/j.addbeh.2016.07.002CrossRefPubMedPubMedCentral

14.

Kendler KS, Ohlsson H, Sundquist K, Sundquist J (2014) The causal nature of the association between neighborhood deprivation and drug abuse: a prospective national Swedish co-relative control study. Psychol Med 44(12):2537–2546. https://doi.org/10.1017/S0033291713003048CrossRefPubMedPubMedCentral

15.

Kendler KS, Sundquist K, Ohlsson H, Palmer K, Maes H, Winkleby MA, Sundquist J (2012) Genetic and familial environmental influences on the risk for drug abuse: a national Swedish adoption study. Arch Gen Psychiatry 69(7):690–697. https://doi.org/10.1001/archgenpsychiatry.2011.2112CrossRefPubMedPubMedCentral

16.

Kendler KS, Lonn SL, Salvatore J, Sundquist J, Sundquist K (2017) Divorce and the onset of alcohol use disorder: a Swedish population-based longitudinal cohort and co-relative study. Am J Psychiatry 174(5):451–458. https://doi.org/10.1176/appi.ajp.2016.16050589CrossRefPubMedPubMedCentral

17.

Edwards AC, Larsson Lonn S, Sundquist J, Kendler KS, Sundquist K (2018) Associations between divorce and onset of drug abuse in a Swedish national sample. Am J Epidemiol 187(5):1010–1018. https://doi.org/10.1093/aje/kwx321CrossRefPubMed

18.

Kendler KS, Ohlsson H, Sundquist K, Sundquist J (2014) Peer deviance, parental divorce, and genetic risk in the prediction of drug abuse in a nationwide Swedish sample: evidence of environment–environment and gene–environment interaction. JAMA Psychiat 71(4):439–445. https://doi.org/10.1001/jamapsychiatry.2013.4166CrossRef

19.

Kendler KS, Ohlsson H, Mezuk B, Sundquist K, Sundquist J (2015) Exposure to peer deviance during childhood and risk for drug abuse: a Swedish national co-relative control study. Psychol Med 45(4):855–864. https://doi.org/10.1017/S0033291714001937CrossRefPubMed

20.

Bountress K, Chassin L, Lemery-Chalfant K (2017) Parent and peer influences on emerging adult substance use disorder: a genetically informed study. Dev Psychopathol 29(1):121–142. https://doi.org/10.1017/S095457941500125XCrossRefPubMed

21.

Livne O, Wengrower T, Feingold D, Shmulewitz D, Hasin DS, Lev-Ran S (2021) Religiosity and substance use in U.S. adults: findings from a large-scale national survey. Drug Alcohol Depend 225:108796. https://doi.org/10.1016/j.drugalcdep.2021.108796CrossRefPubMedPubMedCentral

22.

Edlund MJ, Harris KM, Koenig HG, Han X, Sullivan G, Mattox R, Tang L (2010) Religiosity and decreased risk of substance use disorders: is the effect mediated by social support or mental health status? Soc Psychiatry Psychiatr Epidemiol 45(8):827–836. https://doi.org/10.1007/s00127-009-0124-3CrossRefPubMed

23.

Hearld KR, Badham A, Budhwani H (2017) Statistical effects of religious participation and marriage on substance use and abuse in racial and ethnic minorities. J Relig Health 56(4):1155–1169. https://doi.org/10.1007/s10943-016-0330-8CrossRefPubMed

24.

Kendler KS, Lonn SL, Salvatore J, Sundquist J, Sundquist K (2016) Effect of marriage on risk for onset of alcohol use disorder: a longitudinal and co-relative analysis in a Swedish national sample. Am J Psychiatry 173(9):911–918. https://doi.org/10.1176/appi.ajp.2016.15111373CrossRefPubMedPubMedCentral

25.

Jang BJ, Schuler MS, Evans-Polce RJ, Patrick ME (2018) Marital status as a partial mediator of the associations between young adult substance use and subsequent substance use disorder: application of causal inference methods. J Stud Alcohol Drugs 79(4):567–577CrossRefPubMedPubMedCentral

26.

Zeng X, Chen Y (2020) Associations of deviant peer affiliation with youths’ substance use disorder abstention motivation: the mediating role of perceived social support and the moderating role of collective identity. J Ethn Subst Abuse. https://doi.org/10.1080/15332640.2020.1777608CrossRefPubMed

27.

King KM, Chassin L (2004) Mediating and moderated effects of adolescent behavioral undercontrol and parenting in the prediction of drug use disorders in emerging adulthood. Psychol Addict Behav 18(3):239–249. https://doi.org/10.1037/0893-164X.18.3.239CrossRefPubMed

28.

Morojele NK, Brook JS (2001) Adolescent precursors of intensity of marijuana and other illicit drug use among adult initiators. J Genet Psychol 162(4):430–450. https://doi.org/10.1080/00221320109597494CrossRefPubMed

29.

Cabriales JA, Cooper TV, Taylor T (2013) Prescription drug misuse, illicit drug use, and their potential risk and protective correlates in a Hispanic college student sample. Exp Clin Psychopharmacol 21(3):235–244. https://doi.org/10.1037/a0031973CrossRefPubMed

30.

NIDA (2019) Substance use and military life DrugFacts. https://www.drugabuse.gov/publications/drugfacts/substance-use-military-life. Accessed 23 Jul 2021

31.

Hoggatt KJ, Jamison AL, Lehavot K, Cucciare MA, Timko C, Simpson TL (2015) Alcohol and drug misuse, abuse, and dependence in women veterans. Epidemiol Rev 37:23–37. https://doi.org/10.1093/epirev/mxu010CrossRefPubMed

32.

Williams K, Ramchand R, Sontag-Padilla L, Kress A, Doyle M, Hawes-Dawson J, Cefalu M, Beckman R, Collins R, Engel C, Meadows S (2018) 2015 Health related behaviors survey: substance use among US active-duty service members. RAND Corporation, Santa Monica. https://doi.org/10.7249/rb9955.7CrossRef

33.

Hoggatt KJ, Lehavot K, Krenek M, Schweizer CA, Simpson T (2017) Prevalence of substance misuse among US veterans in the general population. Am J Addict 26(4):357–365. https://doi.org/10.1111/ajad.12534CrossRefPubMed

34.

Wagner TH, Harris KM, Federman B, Dai L, Luna Y, Humphreys K (2007) Prevalence of substance use disorders among veterans and comparable nonveterans from the National Survey on Drug Use and Health. Psychol Serv 4(3):149–157. https://doi.org/10.1037/1541-1559.4.3.149CrossRef

35.

Ahronson A, Cameron JE (2010) The nature and consequences of group cohesion in a military sample. Mil Psychol 19(1):9–25. https://doi.org/10.1080/08995600701323277CrossRef

36.

Oliver LW, Harman J, Hoover E, Hayes SM, Pandhi NA (2009) A quantitative integration of the military cohesion literature. Mil Psychol 11(1):57–83. https://doi.org/10.1207/s15327876mp1101_4CrossRef

37.

Hjalmarsson R, Lindquist MJ (2019) The causal effect of military conscription on crime*. Econ J 129(622):2522–2562. https://doi.org/10.1093/ej/uez014CrossRef

38.

Kelley ML, Brancu M, Robbins AT, D’Lima GM, Strauss JL, Curry JF, Fairbank JA, Runnals J, Va Mid-Atlantic Mirecc Women Veterans Workgroup VAM-AMW (2015) Drug use and childhood-, military- and post-military trauma exposure among women and men veterans. Drug Alcohol Depend 152:201–208. https://doi.org/10.1016/j.drugalcdep.2015.03.038CrossRefPubMed

39.

Kelley ML, Runnals J, Pearson MR, Miller M, Fairbank JA, Workgroup VAM-AMWV, Workgroup VAM-AMR, Brancu M (2013) Alcohol use and trauma exposure among male and female veterans before, during, and after military service. Drug Alcohol Depend 133(2):615–624. https://doi.org/10.1016/j.drugalcdep.2013.08.002CrossRefPubMedPubMedCentral

40.

Hahn AM, Tirabassi CK, Simons RM, Simons JS (2015) Military sexual trauma, combat exposure, and negative urgency as independent predictors of PTSD and subsequent alcohol problems among OEF/OIF veterans. Psychol Serv 12(4):378–383. https://doi.org/10.1037/ser0000060CrossRefPubMedPubMedCentral

41.

Campbell MS, O’Gallagher K, Smolenski DJ, Stewart L, Otto J, Belsher BE, Evatt DP (2021) Longitudinal relationship of combat exposure with mental health diagnoses in the military health system. Mil Med 186(Suppl 1):160–166. https://doi.org/10.1093/milmed/usaa301CrossRefPubMed

42.

Kendler KS, Neale MC, MacLean CJ, Heath AC, Eaves LJ, Kessler RC (1993) Smoking and major depression. A causal analysis. Arch Gen Psychiatry 50(1):36–43. https://doi.org/10.1001/archpsyc.1993.01820130038007CrossRefPubMed

43.

Munafó M, Davey Smith G (2018) Repeating experiments is not enough. Nature 553:399–401PubMed

44.

Lawlor DA, Tilling K, Davey Smith G (2016) Triangulation in aetiological epidemiology. Int J Epidemiol 45(6):1866–1886. https://doi.org/10.1093/ije/dyw314CrossRefPubMed

45.

Kendler KS, Ohlsson H, Sundquist J, Sundquist K (2021) Family genetic risk scores and the genetic architecture of major affective and psychotic disorders in a Swedish national sample. JAMA Psychiat 78(7):735–743. https://doi.org/10.1001/jamapsychiatry.2021.0336CrossRef

46.

Cederlof R, Friberg L, Lundman T (1977) The interactions of smoking, environment and heredity and their implications for disease etiology. A report of epidemiological studies on the Swedish twin registries. Acta Med Scand Suppl 612:1–128PubMed

47.

SAS 9.4 (2012) SAS/STAT^® online documentation, version 9.4. SAS Institute Inc., Cary

48.

Reifman A, Windle M (1996) Vietnam combat exposure and recent drug use: a national study. J Trauma Stress 9(3):557–568. https://doi.org/10.1007/BF02103664CrossRefPubMed

49.

Koffel E, Kramer MD, Arbisi PA, Erbes CR, Kaler M, Polusny MA (2016) Personality traits and combat exposure as predictors of psychopathology over time. Psychol Med 46(1):209–220. https://doi.org/10.1017/S0033291715001798CrossRefPubMed

50.

Gallaway MS, Fink DS, Millikan AM, Mitchell MM, Bell MR (2013) The association between combat exposure and negative behavioral and psychiatric conditions. J Nerv Ment Dis 201(7):572–578. https://doi.org/10.1097/NMD.0b013e318298296aCrossRefPubMed

51.

Yalch MM, Hebenstreit CL, Maguen S (2018) Influence of military sexual assault and other military stressors on substance use disorder and PTS symptomology in female military veterans. Addict Behav 80:28–33. https://doi.org/10.1016/j.addbeh.2017.12.026CrossRefPubMed

52.

Forkus SR, Rosellini AJ, Monteith LL, Contractor AA, Weiss NH (2020) Military sexual trauma and alcohol misuse among military veterans: the roles of negative and positive emotion dysregulation. Psychol Trauma 12(7):716–724. https://doi.org/10.1037/tra0000604CrossRefPubMedPubMedCentral

53.

Gilmore AK, Brignone E, Painter JM, Lehavot K, Fargo J, Suo Y, Simpson T, Carter ME, Blais RK, Gundlapalli AV (2016) Military sexual trauma and co-occurring posttraumatic stress disorder, depressive disorders, and substance use disorders among returning afghanistan and iraq veterans. Womens Health Issues 26(5):546–554. https://doi.org/10.1016/j.whi.2016.07.001CrossRefPubMedPubMedCentral

54.

Dabbs C, Watkins EY, Fink DS, Eick-Cost A, Millikan AM (2014) Opiate-related dependence/abuse and PTSD exposure among the active-component U.S. military, 2001 to 2008. Mil Med 179(8):885–890. https://doi.org/10.7205/MILMED-D-14-00012CrossRefPubMed

55.

Banducci AN, McCaughey VK, Gradus JL, Street AE (2019) The associations between deployment experiences, PTSD, and alcohol use among male and female veterans. Addict Behav 98:106032. https://doi.org/10.1016/j.addbeh.2019.106032CrossRefPubMed

56.

Trautmann S, Schonfeld S, Behrendt S, Schafer J, Hofler M, Zimmermann P, Wittchen HU (2015) Associations between lifetime PTSD symptoms and current substance use disorders using a five-factor model of PTSD. J Anxiety Disord 29:93–100. https://doi.org/10.1016/j.janxdis.2014.11.009CrossRefPubMed

57.

Javidi H, Yadollahie M (2012) Post-traumatic stress disorder. Int J Occup Environ Med 3(1):2–9PubMed

58.

Danielson CK, Amstadter AB, Dangelmaier RE, Resnick HS, Saunders BE, Kilpatrick DG (2009) Trauma-related risk factors for substance abuse among male versus female young adults. Addict Behav 34(4):395–399. https://doi.org/10.1016/j.addbeh.2008.11.009CrossRefPubMed

59.

Bachman JG, Freedman-Doan P, O’Malley PM, Johnston LD, Segal DR (1999) Changing patterns of drug use among US military recruits before and after enlistment. Am J Public Health 89(5):672–677. https://doi.org/10.2105/ajph.89.5.672CrossRefPubMedPubMedCentral

60.

Robins LN (1993) The sixth Thomas James Okey Memorial Lecture. Vietnam veterans’ rapid recovery from heroin addiction: a fluke or normal expectation? Addiction 88(8):1041–1054. https://doi.org/10.1111/j.1360-0443.1993.tb02123.xCrossRefPubMed

61.

Bray RM, Pemberton MR, Lane ME, Hourani LL, Mattiko MJ, Babeu LA (2010) Substance use and mental health trends among U.S. military active duty personnel: key findings from the 2008 DoD Health Behavior Survey. Mil Med 175(6):390–399. https://doi.org/10.7205/milmed-d-09-00132CrossRefPubMed

62.

Connorton E, Perry MJ, Hemenway D, Miller M (2011) Occupational trauma and mental illness–combat, peacekeeping, or relief work and the national co-morbidity survey replication. J Occup Environ Med 53(12):1360–1363. https://doi.org/10.1097/JOM.0b013e318234e2ecCrossRefPubMedPubMedCentral

63.

Hassija CM, Jakupcak M, Maguen S, Shipherd JC (2012) The influence of combat and interpersonal trauma on PTSD, depression, and alcohol misuse in U.S. Gulf War and OEF/OIF women veterans. J Trauma Stress 25(2):216–219. https://doi.org/10.1002/jts.21686CrossRefPubMed

64.

Scherrer JF, Xian H, Lyons MJ, Goldberg J, Eisen SA, True WR, Tsuang M, Bucholz KK, Koenen KC (2008) Posttraumatic stress disorder; combat exposure; and nicotine dependence, alcohol dependence, and major depression in male twins. Compr Psychiatry 49(3):297–304. https://doi.org/10.1016/j.comppsych.2007.11.001CrossRefPubMedPubMedCentral

65.

Shanley M, Hardison C (2016) Essential skills veterans gain during professional military training: a resource for leaders and hiring managers. RAND Corporation, Santa Monica. https://doi.org/10.7249/tl160.2-2CrossRef

66.

Chargualaf KA, Elliott B (2019) Psychological effects of military service: applying research to civilian & academic environments. OJIN Online J Issues Nurs 24(3):Manuscript 2

67.

Hackney KJ, McAllister CP, Mackey JD, Palmer JC, Perrewé PL (2016) From soldier to citizen: examining the role of political skill in veterans’ experiences in the civilian workplace. In: Antoniou A-S, Cooper CL (eds) Coping, personality, and the workplace. Routledge, London

68.

Karney BR, Loughran DS, Pollard MS (2012) Comparing marital status and divorce status in civilian and military populations. J Fam Issues 33(12):1572–1594. https://doi.org/10.1177/0192513X12439690CrossRef

69.

Routon PW (2013) The effect of 21st century military service on civilian labor and educational outcomes. J Labor Res 35(1):15–38. https://doi.org/10.1007/s12122-013-9170-4CrossRef

70.

Angrist JD (1998) Estimating the labor market impact of voluntary military service using social security data on military applicants. Econometrica 66(2):249–288. https://doi.org/10.2307/2998558CrossRef

71.

Aschbacher K, Mellon SH, Wolkowitz OM, Henn-Haase C, Yehuda R, Flory JD, Bierer LM, Abu-Amara D, Marmar CR, Mueller SG (2018) Posttraumatic stress disorder, symptoms, and white matter abnormalities among combat-exposed veterans. Brain Imaging Behav 12(4):989–999. https://doi.org/10.1007/s11682-017-9759-yCrossRefPubMed

72.

Born JA, Zamorski MA (2019) Contribution of traumatic deployment experiences to the burden of mental health problems in Canadian Armed Forces personnel: exploration of population attributable fractions. Soc Psychiatry Psychiatr Epidemiol 54(2):145–156. https://doi.org/10.1007/s00127-018-1562-6CrossRefPubMed

73.

Teachman J, Anderson C, Tedrow LM (2014) Military service and alcohol use in the United States. Armed Forces Soc 41(3):460–476. https://doi.org/10.1177/0095327x14543848CrossRef

74.

Ames G, Cunradi C (2004) Alcohol use and preventing alcohol-related problems among young adults in the military. Alcohol Res Health 28(4):252–257PubMedCentral

75.

Kendler KS, Ohlsson H, Sundquist K, Sundquist J (2016) The rearing environment and risk for drug abuse: a Swedish national high-risk adopted and not adopted co-sibling control study. Psychol Med. https://doi.org/10.1017/S0033291715002858CrossRefPubMedPubMedCentral

76.

Kraus L, Augustin R, Frischer M, Kummler P, Uhl A, Wiessing L (2003) Estimating prevalence of problem drug use at national level in countries of the European Union and Norway. Addiction 98(4):471–485. https://doi.org/10.1046/j.1360-0443.2003.00326.xCrossRefPubMed

77.

Hibell B, Guttormsson R, Ahlström S, Balakireva O, Bjarnason T, Kokkevi A, Kraus L (2009) The 2007 ESPAD Report: substance use among students in 35 European countries. Swedish Council for Information on Alcohol and Other Drugs, Stockholm

78.

Chowdhury R, Shah D, Payal AR (2017) Healthy worker effect phenomenon: revisited with emphasis on statistical methods—a review. Indian J Occup Environ Med 21(1):2–8. https://doi.org/10.4103/ijoem.IJOEM_53_16CrossRefPubMedPubMedCentral

Titel: Military service and risk of subsequent drug use disorders among Swedish men
verfasst von: Alexis C. Edwards
Henrik Ohlsson
Peter B. Barr
Jan Sundquist
Kenneth S. Kendler
Kristina Sundquist
Publikationsdatum: 21.01.2023
Verlag: Springer Berlin Heidelberg
Erschienen in: Social Psychiatry and Psychiatric Epidemiology / Ausgabe 7/2023
Print ISSN: 0933-7954
Elektronische ISSN: 1433-9285
DOI: https://doi.org/10.1007/s00127-023-02426-y

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Military service and risk of subsequent drug use disorders among Swedish men