Subgroups of comorbid PTSD and AUD in U.S. military veterans predict differential responsiveness to two integrated treatments: A latent class analysis

Abstract

Posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD) frequently co-occur. Integrated treatments are effective, but not all patients respond and predicting outcome remains difficult. In this study, latent class analysis (LCA) identified symptom-based subgroups of comorbid PTSD/AUD among 119 veterans with PTSD/AUD from a randomized controlled trial of integrated exposure therapy (I-PE) versus integrated coping skills therapy (I-CS). Multilevel models compared subgroups on PTSD severity and percentage of heavy drinking days at post-treatment and 3- and 6-month follow-up. LCA revealed three subgroups best fit the data: Moderate PTSD/Low AUD Impairment (21%), High PTSD/High AUD Impairment (48%), and Low PTSD/High AUD Impairment (31%). There was a three-way interaction between time, treatment condition, and subgroup in predicting PTSD outcomes (p < .05). For the Moderate PTSD/Low AUD Impairment class, outcomes at post-treatment and 3-months were similar (ds = 0.17, 0.55), however I-PE showed greater reductions at 6-months (d = 1.36). For the High PTSD/High AUD Impairment class, I-PE demonstrated better post-treatment (d = 0.83) but comparable follow-up (ds = −0.18, 0.49) outcomes. For the Low PTSD/High AUD Impairment class, I-PE demonstrated stronger outcomes at every timepoint (ds = 0.82–1.15). Heavy drinking days declined significantly through follow-up, with an effect of subgroup, but not treatment, on timing of response. This was the first study modeling how PTSD and AUD symptoms might cluster together in a treatment sample of veterans with PTSD/AUD. Symptom-based subgroups show promise in helping understand variability in treatment response among patients with PTSD/AUD and deserve further study.