Mild traumatic brain injury (mTBI), depression, and posttraumatic stress disorder (PTSD) are a notable triad in Operation Enduring Freedom, Operation Iraqi Freedom, and Operation New Dawn (OEF/OIF/OND) Veterans. With the comorbidity of depression and PTSD in Veterans with mTBI histories, and their role in exacerbating cognitive and emotional dysfunction, interventions addressing cognitive and psychiatric functioning are critical. Compensatory Cognitive Training (CCT) is associated with improvements in areas such as prospective memory, attention, and executive functioning and has also yielded small-to-medium treatment effects on PTSD and depressive symptom severity. Identifying predictors of psychiatric symptom change following CCT would further inform the interventional approach. We sought to examine neuropsychological predictors of PTSD and depressive symptom improvement in Veterans with a history of mTBI who received CCT.

37 OEF/OIF/OND Veterans with mTBI history and cognitive complaints received 10-weekly 120-minute CCT group sessions as part of a clinical trial. Participants completed a baseline neuropsychological assessment including tests of premorbid functioning, attention/working memory, processing speed, verbal learning/memory, and executive functioning, and completed psychiatric symptom measures (PTSD Checklist-Military Version; Beck Depression Inventory-II) at baseline, post-treatment, and 5-week follow-up. Paired samples t-tests were used to examine statistically significant change in PTSD (total and symptom cluster scores) and depressive symptom scores over time. Pearson correlations were calculated between neuropsychological scores and PTSD and depressive symptom change scores at post-treatment and follow-up. Neuropsychological measures identified as significantly correlated with psychiatric symptom change scores (p^.05) were entered as independent variables in separate multiple linear regression analyses to predict symptom change at post-treatment and follow-up.

Over 50% of CCT participants had clinically meaningful improvement in depressive symptoms (>17.5% score reduction) and over 20% had clinically meaningful improvement in PTSD symptoms (>10-point improvement) at post-treatment and follow-up. Examination of PTSD symptom cluster scores (re-experiencing, avoidance/numbing, and arousal) revealed a statistically significant improvement in avoidance/numbing at follow-up. Bivariate correlations indicated that worse baseline performance on D-KEFS Category Fluency was moderately associated with PTSD symptom improvement at post-treatment. Worse performance on both D-KEFS Category Fluency and Category Switching Accuracy was associated with improvement in depressive symptoms at post-treatment and follow-up. Worse performance on D-KEFS Trail Making Test Switching was associated with improvement in depressive symptoms at follow-up. Subsequent regression analyses revealed worse processing speed and worse aspects of executive functioning at baseline significantly predicted depressive symptom improvement at post-treatment and follow-up.

Worse baseline performances on tests of processing speed and aspects of executive functioning were significantly associated with improvements in PTSD and depressive symptoms during the trial. Our results suggest that cognitive training may bolster skills that are helpful for PTSD and depressive symptom reduction and that those with worse baseline functioning may benefit more from treatment because they have more room to improve. Although CCT is not a primary treatment for PTSD or depressive symptoms, our results support consideration of including CCT in hybrid treatment approaches. Further research should examine these relationships in larger samples.