What's in a name? A data-driven method to identify optimal psychotherapy classifications to advance treatment research on co-occurring PTSD and substance use disorders.

Background/objective: The present study leveraged the expertise of an international group of posttraumatic stress and substance use disorder (PTSD+SUD) intervention researchers to identify which methods of categorizing interventions which target SUD, PTSD, or PTSD+SUD for populations with both PTSD+SUD may be optimal for advancing future systematic reviews, meta-analyses, and comparative effectiveness studies which strive to compare effects across a broad variety of psychotherapy types.

Method: A two-step process was used to evaluate the categorization terminology. First, we searched the literature for pre-existing categories of PTSD+SUD interventions from PTSD+SUD clinical trials, systematic and literature reviews. Then, we surveyed international trauma and substance use subject matter experts about their opinions on pre-existing intervention categorization and ideal categorization nomenclature.

Results: Mixed method analyses revealed that a proliferation of PTSD+SUD treatment research over the last twenty years brought with it an abundance of ways to characterize the treatments that have been evaluated. Results from our survey of experts ( = 27) revealed that interventions for PTSD+SUD can be classified in many ways that appear to overlap highly with one another. Many experts (11/27; 41%) selected the categories of 'trauma-focused and non-trauma focused' as an optimal way to distinguish treatment types. Although several experts reinforced this point during the subsequent meeting, it became clear that no method of categorizing treatments is without flaws.

Conclusion: One possible categorization (trauma-focused/non-trauma focused) was identified. Revised language and nomenclature for classification of PTSD+SUD treatments are needed in order to accommodate the needs of this advancing field.