Abstract
Non-suicidal self-injury (NSSI) and suicidal ideation (SI) represent significant mental health challenges among university students. In low- and middle-income contexts like Bangladesh, there is limited understanding of how these behaviors differentially affect students with and without mental illness. This study addresses these gaps by investigating the prevalence and risk factors of NSSI and SI, with stratified analyses by mental illness status, to predict these behaviors. This cross-sectional study recruited 1401 university students between December 2024 and January 2025. Data was collected via a self-administered questionnaire assessing socio-demographics, and psychological factors. Traditional statistical analyses, including chi-square tests and logistic regression, were conducted in SPSS 27. The prevalence of NSSI and SI was 21.4% and 17.2%, respectively. Both NSSI and SI were more common among students with symptoms of depression or anxiety (mental illness) than those without. Multivariable analyses identified smoking, cyberbullying, and probable eating disorder as significant predictors of both NSSI and SI, with these associations persisting after stratification by mental illness status. Subgroup analyses showed that among students without mental illness, female gender, older age, smoking, cyberbullying, and eating disorder symptoms significantly predicted NSSI, while smoking, cyberbullying, eating disorder, and older age predicted SI. In students with mental illness, smoking and cyberbullying remained robust predictors of both NSSI and SI, while eating disorder was significantly associated with NSSI but not SI. The regression models explained 12.9% of the variance in NSSI and 16.6% in SI. The findings highlight the necessity to adopt interventions that address modifiable risk factors, with a strong emphasis on behavioral and mental health variables, to effectively reduce self-harming and suicidal behaviors in young adults.