The Impact of Depression Severity on Treatment Outcomes Among Older Male Combat Veterans with Posttraumatic Stress Disorder.

Posttraumatic stress disorder (PTSD) and depression are highly comorbid within the veteran population. Research studies have yielded divergent findings regarding the effect of depression on PTSD treatment outcomes. The present study investigated the influence of pretreatment depression severity on PTSD and depression symptom trajectories among 85 older (i.e., ≥ 60 years) male veterans with military-related PTSD who received either prolonged exposure or relaxation training as part of a randomized controlled trial. Participants were categorized as having no/mild depression (n = 23) or moderate/severe depression (n = 62). The PTSD Checklist (PCL-S) and Patient Health Questionnaire (PHQ-9) were completed at pretreatment, each of 12 therapy sessions, posttreatment, and 6-month follow-up, for a total of up to 15 data points per participant. Multilevel modeling (MLM) was used to evaluate the impact of pretreatment depression severity on piecewise symptom trajectories (i.e., active treatment and follow-up periods) over time and to determine whether treatment condition moderated the trajectories. The final MLM results showed significant main effects of depression severity on PCL-S scores, B = 10.84, p = .043 and PHQ-9 scores, B = 7.09, p = .001, over time. No significant interactions emerged for either the PCL-S or PHQ-9, indicating that although older veterans with more severe depression endorsed higher PTSD and depression scores across time, the symptom trajectories were not moderated by depression severity, treatment condition, or their interaction.