Longitudinal invariance of posttraumatic stress disorder symptoms in adolescent earthquake survivors

► The invariance of four models of PTSD symptoms across time was examined. ► The three alternative models were superior to the model defined in DSM-IV. ► Four tested models were non-invariant over time on intercepts and error variances. ► Factor loadings and structural parameters were invariant across time for all models. ► The newly proposed five factors model fit slightly better than four-factor models.