This observational, cross-sectional study examined students' retrospective recall of emotional distress when studying sensitive topics in psychology, and whether hardiness had a mediated pathway to emotional distress through a mental health condition (MHC). Psychology undergraduates (155 women, 34 men) from South Australian universities completed self-report questionnaires assessing hardiness, retrospective measures of emotional distress when studying a range of topics, their concurrent MHC and lifetime cumulative trauma. As hypothesised, students reported more emotional distress to sensitive topics relative to nonsensitive ones, p < 0.001 (r = -0.69). Hardiness was significantly negatively correlated with MHC, p < 0.001 (r = -0.38). Causal mediation analysis revealed, as predicted, that MHC mediated the effect of hardiness on emotional distress (p < 0.001). These results are consistent with existing literature on students' reactions to sensitive topics in medical, law and social work education, as well as previous findings of negative associations between hardiness and mental health outcomes. Implications for higher education policy and practice are discussed, including the use of hardiness assessments as an early screening tool for mental health decline. Future research should identify the specific MHCs involved in the mediated pathway from hardiness to course-related emotional distress, and employ longitudinal designs to confirm the temporal ordering of variables.