Posttraumatic Stress Disorder among Registered Nurses and Nursing Students in Italy during the COVID-19 Pandemic: A Cross-Sectional Study

(1) Background: Posttraumatic stress disorder (PTSD) is a mental health disorder characterized by a range of syndromal responses to extreme stressors. The present study aimed to explore any differences in PTSD between registered nurses and nursing students, according to sex and nursing experience, during the COVID-19 pandemic. (2): Methods: An observational descriptive study was conducted among Italian nurses and nursing students during the first wave of the COVID-19 pandemic. An online questionnaire was distributed in an anonymous form through the Google function of Google Modules to some social pages and nursing groups. (3) Results: In total, 576 participants were enrolled in this study. Of these, 291 (50.50%) were registered nurses and 285 (49.50%) were nursing students. By considering the Impact of Event Scale—Revised values in nurses and in nursing students according to sex, a significant difference was reported in the avoidance sub-dimension (p = 0.024), as female nurses recorded higher levels than nursing students. No further significant differences were suggested by considering both sex and nursing experience, respectively. (4) Conclusion: PTSD could be a serious consequence for both nurses and nursing students during the COVID-19 pandemic.