Prevalence of self-reported prior mental health diagnosis and associated factors among undergraduate students in a Nigerian private university

The history of prior mental health diagnosis among undergraduate students has become a growing concern in higher education institutions globally. This study aimed to investigate the prevalence of self-reported prior mental health diagnosis as well as the sociodemographic, social and academic factors associated with such diagnoses among undergraduate students at Afe Babalola University. A cross-sectional study design was employed, utilising a self-administered structured questionnaire to collect data from 354 undergraduate students selected through multistage sampling. Data were analysed using adjusted binary logistic regression to assess the association between a history of prior mental health diagnosis and various social and academic factors. IBM SPSS Statistics version 27.0 was used for the analysis. The study found that 9.6% ( n = 34) of the participants reported having previously received a formal diagnosis of at least one mental health condition from a healthcare professional. Among students who reported a prior diagnosis, depression was the most commonly reported condition, affecting 18 (52.9% ( n = 18)) of the students, followed by anxiety (15, 44.1%, n = 15), stress (5, 14.7%, n = 5) and schizophrenia (3, 8.8% ( n = 3)). Being female was significantly associated with higher odds of a prior mental health diagnosis compared to males (AOR: 6.574, 95% CI 1.992–21.692, p = 0.002). Students who reported having strong social and family support had significantly lower odds of a prior mental health diagnosis compared to those without such support (AOR: 0.225, 95% CI 0.062–0.809, p = 0.022). Students who reported having missed too many classes during the semester had significantly higher odds of a prior mental health diagnosis compared to those who had not (AOR: 11.030, 95% CI 2.877–42.287, p < 0.001). This study found a low prevalence of prior history of formal mental health diagnosis, with depression being the most commonly reported condition. Female gender and high-class absenteeism were associated with increased odds of a prior diagnosis while strong social and family support emerged as the only significant protective factor. The university should prioritise gender-sensitive mental health services, absenteeism-based welfare referral systems, and initiatives that strengthen social connectedness among students. Future research should assess current mental health status alongside prior diagnosis history using validated instruments and longitudinal designs.