OPENING PLENARY
"Longitudinal Studies in PTSD: a Clinician-Researcher Perspective"

Among the anxiety disorders, PTSD is characterized by having a salient point of onset and early, discernable symptoms. Notwithstanding, the disorder’s main features and the presumed link with a traumatic event were inferred retrospectively, from studies of chronic patients. It is only later that longitudinal studies came to substantiate – and somewhat qualify – both the link between a traumatic event and PTSD and the trajectories that early stress responses take. Longitudinal studies may effectively address some questions, yet they are expensive, labor intensive, and have their own inherent limitations and pitfalls. Specifically, this presentation will address the history of longitudinal studies in trauma research, outline some of the important findings, and address the concerns we face in using longitudinal approaches, from the most obvious (sampling and attrition) to the more subtle yet cardinal issues of modeling, analyses, interpretation of findings, inferences, and generalizability.