3.1.Demographic and diagnostic information
Demographic data and psychiatric morbidity rates are presented in . Seventy-eight percent of the sample was male, with a sample mean age of 37. The majority was African American or Caucasian, employed, and currently married. Sixty-eight percent served in the Iraq or Afghanistan theaters. Psychiatric morbidity rates are presented in . Rates were 30% for current PTSD, 20% for current MDD, 6% for current SUD, 38% for lifetime SUD, and 10% for presence of any other current Axis I psychiatric disorder. Of the 107 (30%) with current PTSD, 44% were diagnosed with comorbid current MDD, and 53% with a lifetime SUD. Of the 70 (20%) participants with current MDD, 67% were diagnosed with comorbid PTSD, and 54% with lifetime SUD. Of the 135 (38%) with a lifetime SUD, 57 (42%) were diagnosed with PTSD, and 38 (28%) were diagnosed with MDD.
Psychiatric morbidity and comorbidity with posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) for entire sample (N = 356).
3.2.Prevalence of traumatic events
Most participants endorsed multiple potentially traumatic events. Seventy-three (21%) participants reported only one traumatic event meeting criterion A, while 59 (17%) reported two traumatic events meeting criterion A, and 204 (57%) reported three or more traumatic events meeting criterion A. Of the 21 potentially traumatic events queried by the TLEQ, the mean number of these events endorsed was 6.3 (SD = 3.4) and ranged from 0 to 17. The mean number of traumatic events meeting criterion A was 3.6 (SD = 2.8). Finally, combat exposure, as measured by CES scores, ranged from 0 to 39 (M = 11.5, SD = 10.5).
The prevalence rates for each of the TLEQ trauma categories are presented in . Results shown include both exposure to events and whether the event endorsed met DSM-IV criterion A. Overall, almost the entire sample (99%) reported exposure to at least one potentially traumatic event. Eighty-eight percent of the respondents endorsed pre-military exposure to potentially traumatic events, 93% reported potentially traumatic event exposure during military service including 71% who reported war-zone exposure, and 53% reported post-military potentially traumatic events.
Potentially traumatic event and intense fear, helplessness, or horror (criterion A) frequencies.
Many individuals reported experiencing events that were life threatening but did not meet the A criterion. For example, intense fear, helplessness, or horror was endorsed by only 53% of veterans reporting an accident or disaster, 65% of veterans endorsing adult physical assault, and 69% of those reporting medical illness/unexpected death. Similarly, although 71% of the sample reported serving in a war-zone, only 50% of the sample reported combat experiences that met criterion A for possible diagnosis of PTSD.
The most frequently reported traumas during military service meeting criterion A were war-zone trauma (49%) and medical illness/unexpected death (44%). The most frequent pre-military trauma exposures satisfying criterion A were childhood physical abuse (37%) and medical illness/unexpected death (32%). The relative frequency of trauma exposure following military service was low, but the most commonly endorsed trauma exposure was medical/unexpected death (21%). The prevalence of reported sexual trauma during and after the military was low (3% and 1%, respectively).
3.3.Logistic regression analyses of psychiatric morbidity by criterion A trauma types – study aim 1
Results of logistic regression analyses are presented in . In the model with current PTSD diagnosis as the outcome, intellectual functioning z-scores were associated with decreased odds of PTSD (OR = 0.62, p < .05). More severe combat exposure (OR = 1.10, p < .01), accident/disaster trauma (OR = 2.20, p < .01), and childhood physical assault (OR = 2.18, p < .05) were associated with increased odds of PTSD. Similarly, analyses examining current MDD as the outcome indicated that higher CES scores (OR = 1.05, p < .01), accident/disaster trauma (OR = 2.92, p < .01), and childhood physical assault (OR = 2.19, p < .05) were associated with increased risk of depression. In addition, adult sexual assault (OR = 3.69, p < .05) was related to increased odds of MDD. Lifetime SUD was associated with male gender (OR = 3.78, p < .01) and adult physical assault (OR = 1.72, p < .05). In a model predicting the presence of any current psychiatric disorder other than PTSD, MDD, or SUD, minority status (OR = 2.63, p < .05) and medical/unexpected death (OR = 2.85, p < .05) were related to increased risk of a psychiatric disorder. When examining the PTSD only participants (no current MDD or lifetime SUD), increased odds of PTSD was associated only with combat exposure (OR = 1.05, p < .01) and adult physical assault (OR = 2.10, p < .05). Regarding the group comprised entirely of participants with both current PTSD and current MDD, increased odds of psychiatric morbidity were associated with combat exposure (OR = 1.10, p < .01), accident/disaster (OR = 3.58, p < .01), and childhood physical assault (OR = 2.56, p < .05).
Summary of logistic regression analyses of psychiatric morbidity: study aim 1.
3.4.Logistic regression analyses of psychiatric morbidity by number of potentially traumatic event exposures – study aim 2
Using age, gender, minority status, and intellectual functioning as covariates, the number of traumatic event exposures was predictive of increased risk of PTSD (OR = 1.14, p < .01), MDD (OR = 1.18, p < .01), SUD (OR = 1.16, p < .01), and the group comprised entirely of comorbid PTSD and MDD (OR = 1.16, p < .01). However, the number of potentially traumatic events was not associated with an increased risk of other psychiatric disorders or the PTSD group without comorbid MDD or SUD.
Repeating these analyses using the number of criterion A traumatic events as the predictor produced the same overall pattern of results. The number of trauma exposures was associated with increased risk of PTSD (OR = 1.14, p < .01), MDD (OR = 1.28, p < .01), SUD (OR = 1.19, p < .01), and the group comprised entirely of participants with both PTSD and MDD (OR = 1.20, p < .01). The number of criterion A traumatic event exposures was not associated with increased risk of other psychiatric disorders, or PTSD without comorbid MDD or SUD.
3.5.Simultaneous regression analyses of psychiatric symptoms among those diagnosed with a psychiatric disorder – study aim 3
Follow-up analyses sought to characterize the influences of covariates and trauma on PTSD symptoms (DTS), depressive symptoms (BDI-II), and alcohol misuse (AUDIT) among those diagnosed with a psychiatric disorder (n = 185). Statistics for predictors that were significantly associated with each of the three outcomes are listed in . In the regression equation with DTS as the outcome, combat exposure (partial R2 = .11, p < .01), medical/ unexpected death trauma (partial R2 = .08, p < .01), and adult physical-assault trauma (partial R2 = .03, p < .05) were related to the outcome. In the regression equation predicting BDI-II scores, combat exposure (partial R2 = .03, p < .05) and medical/unexpected-death trauma (partial R2 = .10, p < .01) were significantly predictive. Only demographic variables, younger age (partial R2 = .10, p < .01) and male gender (partial R2 = .03, p < .05), were associated with elevated AUDIT scores.
Summary of significant predictors of psychiatric symptom outcomes in patients with at least one Axis I disorder: study aim 2.