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BACKGROUND: Investigations of drinking behavior across military deployment cycles are scarce, and few prospective studies have examined risk factors for post-deployment alcohol misuse. METHODS: Prevalence of alcohol misuse was estimated among 4,645 U.S. Army soldiers who participated in a longitudinal survey. Assessment occurred 1–2 months before soldiers deployed to Afghanistan in 2012 (T0), upon their return to the U.S. (T1), 3 months later (T2), and 9 months later (T3). Weights-adjusted logistic regression was used to evaluate associations of hypothesized risk factors with post-deployment incidence and persistence of heavy drinking (consuming 5+ alcoholic drinks at least 1–2×/week) and Alcohol or Substance Use Disorder (AUD/SUD). RESULTS: Prevalence of past-month heavy drinking at T0, T2, and T3 was 23.3% (SE=0.7%), 26.1% (SE=0.8%), and 22.3% (SE=0.7%); corresponding estimates for any binge drinking were 52.5% (SE=1.0%), 52.5% (SE=1.0%), and 41.3% (SE=0.9%). Greater personal life stress during deployment (e.g., relationship, family, or financial problems) – but not combat stress – was associated with new onset of heavy drinking at T2 [per standard score increase: AOR=1.20, 95% CI 1.06–1.35, p=.003]; incidence of AUD/SUD at T2 (AOR=1.54, 95% CI 1.25–1.89, p<.0005); and persistence of AUD/SUD at T2 and T3 (AOR=1.30, 95% CI 1.08–1.56, p=.005). Any binge drinking pre-deployment was associated with post-deployment onset of HD (AOR=3.21, 95% CI 2.57–4.02, p<.0005) and AUD/SUD (AOR=1.85, 95% CI 1.27–2.70, p=.001). CONCLUSIONS: Alcohol misuse is common during the months preceding and following deployment. Timely intervention aimed at alleviating/managing personal stressors or curbing risky drinking might reduce risk of alcohol-related problems post-deployment.

OBJECTIVE: To investigate associations of lifetime traumatic brain injury (LT-TBI) prior to an index deployment, and/or deployment-acquired TBI (DA-TBI), with post-deployment binge and heavy drinking. SETTING: Soldiers from 3 Brigade Combat Teams deployed to Afghanistan in 2012. PARTICIPANTS: 4,645 Soldiers who participated in the Army STARRS Pre/Post Deployment Study and completed 4 assessments: T0 (1–2 months pre-deployment), T1 (upon return to U.S.), T2 (3-months post-deployment), and T3 (9-months post-deployment). DESIGN: Prospective, longitudinal study controlling for baseline binge drinking. MAIN MEASURES: Self-reported past month binge drinking (5+ alcoholic beverages on the same day) and past month heavy drinking (binge drinking at least weekly) at T2 and T3. RESULTS: 34.3% screened positive for LT-TBI, and 19.2% screened positive for DA-TBI. At T2 only, LT-TBI, but not DA-TBI, was associated with increased odds of binge drinking [adjusted odds ratio (AOR) = 1.39, 95% CI 1.20–1.60, p < .001] and heavy drinking [AOR = 1.28, 95% CI 1.09–1.49, p = .007]. Among the subgroup with LT-TBI, also having DA-TBI was associated with increased risk of heavy drinking at T3 [AOR = 1.42. 95% CI 1.03–1.95, p = 0.047]. CONCLUSION: Routine screening for LT-TBI may help target efforts to prevent alcohol misuse among military members.

Traumatic brain injury (TBI) contributes to the increased rates of suicide and post-traumatic stress disorder in military personnel and veterans, and it is also associated with the risk for neurodegenerative and psychiatric disorders. A cross-phenotype high-resolution polygenic risk score (PRS) analysis of persistent post-concussive symptoms (PCS) was conducted in 845 U.S. Army soldiers who sustained TBI during their deployment. We used a prospective longitudinal survey of three brigade combat teams to assess deployment-acquired TBI and persistent physical, cognitive, and emotional PCS. PRS was derived from summary statistics of large genome-wide association studies of Alzheimer's disease, Parkinson's disease, schizophrenia, bipolar disorder, and major depressive disorder (MDD); and for years of schooling, college completion, childhood intelligence, infant head circumference (IHC), and adult intracranial volume. Although our study had more than 95% of statistical power to detect moderate-to-large effect sizes, no association was observed with neurodegenerative and psychiatric disorders, suggesting that persistent PCS does not share genetic components with these traits to a moderate-to-large degree. We observed a significant finding: subjects with high IHC PRS recovered better from cognitive/emotional persistent PCS than the other individuals (R2 = 1.11%; p = 3.37 × 10−3). Enrichment analysis identified two significant Gene Ontology (GO) terms related to this result: GO:0050839∼Cell adhesion molecule binding (p = 8.9 × 10−6) and GO:0050905∼Neuromuscular process (p = 9.8 × 10−5). In summary, our study indicated that the genetic predisposition to persistent PCS after TBI does not have substantial overlap with neurodegenerative and psychiatric diseases, but mechanisms related to early brain growth may be involved.

Mild traumatic brain injury (mTBI), or concussion, is prevalent in the military. The course of recovery can be highly variable. This study investigates whether deployment-acquired mTBI is associated with subsequent presence and severity of post-concussive symptoms (PCS) and identifies predictors of persistent PCS among US Army personnel who sustained mTBI while deployed to Afghanistan. We used data from a prospective longitudinal survey of soldiers assessed 1–2 months before a 10-month deployment to Afghanistan (T0), on redeployment to the United States (T1), approximately 3 months later (T2), and approximately 9 months later (T3). Outcomes of interest were PCS at T2 and T3. Predictors considered were: sociodemographic factors, number of previous deployments, pre-deployment mental health and TBI history, and mTBI and other military-related stress during the index deployment. The study sample comprised 4518 soldiers, 822 (18.2%) of whom experienced mTBI during the index deployment. After adjusting for demographic, clinical, and deployment-related factors, deployment-acquired mTBI was associated with nearly triple the risk of reporting any PCS and with increased severity of PCS when symptoms were present. Among those who sustained mTBI, severity of PCS at follow-up was associated with history of pre-deployment TBI(s), pre-deployment psychological distress, more severe deployment stress, and loss of consciousness or lapse of memory (versus being "dazed" only) as a result of deployment-acquired mTBI. In summary, we found that sustaining mTBI increases risk for persistent PCS. Previous TBI(s), pre-deployment psychological distress, severe deployment stress, and loss of consciousness or lapse of memory resulting from mTBI(s) are prognostic indicators of persistent PCS after an index mTBI. These observations may have actionable implications for prevention of chronic sequelae of mTBI in the military and other settings.

BACKGROUND: Prior investigations have found negative associations between military unit cohesion and posttraumatic stress disorder (PTSD); however, most relied on cross-sectional data and few examined relationships of unit cohesion to other mental disorders. This study evaluates prospective associations of perceived unit cohesion with a range of mental health outcomes following combat deployment. METHODS: US Army soldiers were surveyed approximately 1–2 months before deployment to Afghanistan (T0); and 1 month (T1), 3 months (T2), and 9 months (T3) after return from deployment. Logistic regression was performed to estimate associations of perceived unit cohesion at T0 with risk of PTSD, major depressive episode (MDE), generalized anxiety disorder (GAD), alcohol or substance use disorder (AUD/SUD), and suicidal ideation at T2 or T3 among soldiers who completed all study assessments (N=4,645). Models adjusted for socio-demographic and Army service characteristics, pre-deployment history of the index outcome, and deployment stress exposure. RESULTS: Higher perceived unit cohesion at T0 was associated with lower risk of PTSD, MDE, GAD, AUD/SUD, and suicidal ideation at T2 or T3 (AORs=0.72 to 0.85 per standard score increase in unit cohesion; ps<.05). Models of incidence of mental disorders and suicidal ideation among soldiers without these problems pre-deployment yielded similar results [AORs=0.65 to 0.79; ps<.01], except that perceived unit cohesion was not associated with incident AUD/SUD. CONCLUSIONS: Soldiers who reported strong unit cohesion before deployment had lower risk of post-deployment mental disorders and suicidal ideation. Awareness of associations of perceived unit cohesion with post-deployment mental health may facilitate targeting of prevention programs.

Insomnia is a worldwide problem with substantial deleterious health effects. Twin studies have shown a heritable basis for various sleep-related traits, including insomnia, but robust genetic risk variants have just recently begun to be identified. We conducted genome-wide association studies (GWAS) of soldiers in the Army Study To Assess Risk and Resilience in Servicemembers (STARRS). GWAS were carried out separately for each ancestral group (EUR, AFR, LAT) using logistic regression for each of the STARRS component studies (including 3,237 cases and 14,414 controls), and then meta-analysis was conducted across studies and ancestral groups. Heritability (SNP-based) for lifetime insomnia disorder was significant (h2g = 0.115, p = 1.78 × 10-4 in EUR). A meta-analysis including three ancestral groups and three study cohorts revealed a genome-wide significant locus on Chr 7 (q11.22) (top SNP rs186736700, OR = 0.607, p = 4.88 × 10-9) and a genome-wide significant gene-based association (p = 7.61 × 10-7) in EUR for RFX3 on Chr 9. Polygenic risk for sleeplessness/insomnia severity in UK Biobank was significantly positively associated with likelihood of insomnia disorder in STARRS. Genetic contributions to insomnia disorder in STARRS were significantly positively correlated with major depressive disorder (rg = 0.44, se = 0.22, p = 0.047) and type 2 diabetes (rg = 0.43, se = 0.20, p = 0.037), and negatively with morningness chronotype (rg = -0.34, se = 0.17, p = 0.039) and subjective well being (rg = -0.59, se = 0.23, p = 0.009) in external datasets. Insomnia associated loci may contribute to the genetic risk underlying a range of health conditions including psychiatric disorders and metabolic disease.