An Exploratory Study of Varying Phenotypes of Posttraumatic Stress Among a Comorbid Substance Misuse Population

Objective: The purpose of this study was to explore differences in presentation of posttraumatic distress (PTD) that may represent different phenotypes, such as a possible cognitively-driven variant, in addition to those rooted in the prevailing conditioned-fear model. In conjunction, links to substance misuse and a purposeful selection bias for specific drugs-of-choice (DoC) based on phenotype variation were examined. Method: A convenience sample of inpatients in residential treatment for substance misuse who also endorsed posttraumatic distress following at least one previous traumatic experience (N = 177) completed self-report assessments and an in-person direct inquiry. Results: Hierarchical cluster analysis and ANOVA results partially supported our hypotheses and provided some evidence of a cognitive-focused phenotype, as well as a possible image/adrenergic-based phenotype. Subsequently, multinomial logistic regression determined that the hypothesized phenotypes were significantly linked to DoC selection, specifically (a) cognitive-focused phenotype predicted primary alcohol/benzodiazepine use (b) image/adrenergic-based phenotype predicted cannabinoid/opiate use, and (c) a traditional “mixed” PTD presentation predicted polysubstance use. Conclusions: Findings from this exploratory study offer additional validation to calls for continued examination of varying phenotypes, as well as a cognitively-driven model, of PTD additional to those based in conditioned-fear. Additionally, evidence was shown for a purpose-driven theory of substance misuse, hallmarked by an underlying maladaptive drive to select a DoC with the capacity to alleviate specific symptomatology (e.g., heavy alcohol use to alleviate excessive rumination and sleep disturbance).