Table.
Sample Characteristics and Results of Total Intracranial Volume-Adjusted Partial Correlationsa
| Characteristic | No. (%) | Amygdala | Hippocampus | ||
|---|---|---|---|---|---|
| Right | Left | Right | Left | ||
| Age, mean (SD), y | 33.1 (7.8) | 0.00 | 0.05 | −0.05 | 0.17 |
| Male | 41 (85.4) | −0.02 | 0.20 | 0.05 | 0.08 |
| White race/ethnicity | 32 (66.7) | −0.07 | −0.20 | −0.17 | −0.11 |
| College or higher education | 13 (27.1) | 0.22 | 0.10 | 0.17 | 0.26 |
| Married/living with partner | 20 (41.7) | 0.01 | −0.04 | 0.08 | 0.17 |
| Lifetime traumatic events (TLEQ score), mean (SD) | 12.3 (6.1) | −0.27 | 0.08 | 0.09 | 0.00 |
| Childhood trauma (CTQ total score), mean (SD) | 42.6 (15.1) | −0.02 | −0.13 | −0.12 | −0.06 |
| Time in service, mean (SD), y | 10.4 (6.8) | 0.06 | 0.01 | 0.03 | 0.15 |
| No. of deployments, mean (SD) | 2.0 (1.3) | −0.05 | −0.10 | −0.03 | −0.01 |
| Combat exposure severity (CES score), mean (SD) | 5.6 (4.4) | −0.36b | −0.14 | −0.23 | −0.32c |
| CAPS total score, mean (SD) | 25.5 (27.0) | −0.39b | −0.16 | −0.26 | −0.20 |
| Reexperiencing | 6.5 (8.1) | −0.35c | −0.15 | −0.27 | −0.24 |
| Avoidance | 2.5 (3.9) | −0.35c | −0.18 | −0.27 | −0.24 |
| Numbing | 5.8 (7.2) | −0.31c | −0.17 | −0.26 | −0.15 |
| Dysphoric arousal | 7.0 (6.9) | −0.33c | −0.07 | −0.14 | −0.08 |
| Anxious arousal | 3.6 (4.0) | −0.45b | −0.16 | −0.25 | −0.20 |
| Chronic PTSD symptoms (≥3 mo) | 4 (8.3) | 0.01 | 0.09 | 0.14 | 0.08 |
| Depressive symptom severity (BDI–II score), mean (SD) | 14.1 (12.7) | −0.11 | −0.06 | 0.03 | −0.02 |
| Psychotropic medication | 12 (25.0) | 0.19 | −0.05 | −0.05 | 0.00 |
| Lifetime dependence | |||||
| Alcohol | 3 (6.3) | −0.17 | −0.09 | −0.18 | −0.21 |
| Nicotine | 5 (10.4) | −0.27 | −0.11 | −0.18 | −0.12 |
Abbreviations: BDI-II, Beck Depression Inventory–II; CAPS, Clinician-Administered PTSD Scale; CES, Combat Experiences Scale; CTQ, Childhood Trauma Questionnaire; PTSD, posttraumatic stress disorder; TLEQ, Traumatic Life Events Questionnaire
A total of 3 multivariable linear regression analyses were conducted: one with main effects of intracranial volume, combat exposure severity, and CAPS scores, and combat exposure severity by CAPS score interaction term; a second with only intracranial volume, combat exposure severity, and CAPS scores; and a third post hoc analysis to evaluate how the 5 PTSD symptom clusters were related to amygdala volume (results reported in the Results section). In the multivariable linear regression analysis, the combat exposure severity by CAPS interaction was not significant (β = −0.01; t = 0.02; P = .98); thus, the final model contained only main effects of total intracranial volume, combat exposure, and CAPS scores.
P < .01.
P < .05.