Protective or Pressuring? Multi-Group Structural Path Analysis of Family–School Support and Mental Health Among Postgraduates

(1) Background: With the continuous expansion of graduate education, the mental health of postgraduates has become a growing concern for both academia and society. Understanding how family and institutional resources influence psychological outcomes is critical for developing effective support strategies; (2) Methods: A cross-sectional survey was conducted among 3998 postgraduate students across China, including 3393 master's students (51.78% female, <i>M</i> = 24.21, <i>SD</i> = 1.521) and 605 doctoral students (37.19% female, <i>M</i> = 27.77, <i>SD</i> = 2.841). Multi-group structural equation modeling was employed to examine how family functioning and supervisor-postgraduate relationships influenced mental health, research self-efficacy, and suicidal tendencies; (3) Results: The findings showed that although most structural relationships were consistent across groups, two critical pathways were nonsignificant at the doctoral stage, providing evidence of partial structural invariance; (4) Conclusions: The study suggests that while family and school support generally play a protective role, their influence varies across educational stages. Tailoring psychological interventions to the distinct needs of master's and doctoral students is essential, offering both theoretical insights into the dual role of contextual resources and practical guidance for targeted mental health support in graduate education.