Changes in posttraumatic stress disorder symptom severity during the COVID-19 pandemic: Ten-wave findings from a longitudinal observational cohort study of community adults.

Few studies have examined changes in posttraumatic-stress disorder (PTSD) symptomatology across an extended time period during the COVID-19 pandemic. This study used a longitudinal cohort design to examine: (1) changes in overall PTSD symptoms and symptom clusters; (2) moderators of change; (3) the clinical significance of observed changes; and (4) correlates of clinically meaningful changes. Community adults (N = 1412) were assessed using the PTSD Checklist for DSM-5 (PCL-5) at 10 timepoints (October 2018 - April 2022). Changes in overall PCL-5 score and symptom clusters were substantially moderated by pre-pandemic clinical severity (i.e., above/below PCL-5 cut-off). Pre-pandemic non-clinical participants exhibited increases in overall scores, Cluster D (negative cognitions), and Cluster E (arousal), while clinically elevated participants exhibited decreases overall and in all clusters. Regarding clinical significance, 12% of pre-pandemic non-clinical participants exhibited clinically meaningful increases, and 4% exhibited decreases. Conversely, 42% of the pre-pandemic elevated group exhibited clinically meaningful decreases, while 6% exhibited increases. Pandemic impacts in numerous psychosocial domains were associated with clinically meaningful change. Collectively, these findings reveal substantively divergent trajectories by pre-pandemic severity and PTSD symptom cluster. The large proportion of pre-pandemic high-severity participants exhibiting sizable decreases was an unexpected notable observation.