ABSTRACT
BACKGROUNDS: PTSD is one of the most common conditions after people have experienced trauma. While previous studies have found a link between PTSD and non-suicidal self-injury, (NSSI), few studies have longitudinally explored this relationship and the underlying mechanisms. AIMS: This study explored adolescent NSSI frequency after COVID-19 lockdown experiences, the relationship with early PTSD symptoms, and the mediating role of depression and sleep problems. METHODS: A cohort of 1609 adolescents completed two surveys during and after the national lockdown in China; one month into the lockdown and six months later; which assessed demographic and pandemic-related exposure variables; PTSD, depression, sleep, and NSSI. Mediation analyses and hierarchical regression were employed to examine the relationships and the paths between these variables. RESULTS: The NSSI rate was found to be 31.9 % after the three-month lockdown, with 20.6 % of adolescent participants reporting sleeping disorders, and 33.9 % indicating probable depression. Adolescents who had earlier PTSD symptoms, often smoked and/or drank, and had current depression and sleep disorders reported greater NSSI. Early PTSD symptoms were found to predict later NSSI and were mediated by sleep problems and depressive symptoms. Specifically, PTSD avoidance and numbing symptoms were significantly associated with NSSI above and beyond the depressive symptoms, sleeping problems, and the other covariables. CONCLUSION: It is necessary to be vigilant about the increased risk of NSSI in adolescents who have experienced extended pandemic lockdowns. Preventing early adolescent PTSD symptoms, especially avoidance and numbness, and helping teenagers quit smoking and drinking could reduce the risk of sleep disorders, depression, and NSSI.