Mediation by elevated prolactin in the relationship between childhood trauma and first-episode drug-naive schizophrenia

Background The elevated prolactin levels in first-episode drug-naive (FEDN) schizophrenia patients may correlate with long-term stress caused by childhood trauma. This study aimed to assess the relationship between elevated prolactin levels and childhood trauma in FEDN schizophrenia patients, while also considering sex differences. Methods Utilizing a cross-sectional design, the study involved 88 FEDN schizophrenia patients and 76 healthy controls (HCs). Evaluations encompassed measuring prolactin levels in peripheral blood and assessing mental health using the Positive and Negative Syndrome Scale (PANSS), the Childhood Trauma Questionnaire - Short Form (CTQ-SF), as well as evaluating resilience with the Connor-Davidson Resilience Scale (CD-RISC), perceived social support with the Perceived Social Support Scale (PSSS), and demographic characteristics to control for confounding factors. A mediation model was constructed using the RMediation package of the R software. Methods The results suggested prolactin levels in FEDN schizophrenia patients were higher than in HCs(t=-9.938, p = 0.000). Group classification (HCs vs. FEDN schizophrenia patients) (t = 9.291, p = 0.000) and sex (t = 3.282, p = 0.001) were influential factors for prolactin levels. Elevated prolactin(OR = 1.007, p = 0.000), along with higher scores for childhood emotional(OR = 1.469, p = 0.006)andsexual abuse(OR = 1.592, p = 0.018) and lower social support(OR = 0.946, p = 0.026), were associated with the onset of schizophrenia. Positive correlations were found between prolactin levels and childhood emotional (r = 0.268, p = 0.002) /sexual abuse(r = 0.264, p = 0.002), with no sex differences. No significant relationship was observed between prolactin levels and PANSS scores. Mediation analysis revealed that childhood emotional abuse (95% CI: [0.059 similar to 0.293]) and sexual abuse (95% CI: [0.086 similar to 0.439]) had significant indirect effects on schizophrenia, mediated by elevated prolactin levels. Conclusion These findings suggest that childhood trauma may be associated with the onset of schizophrenia by influencing prolactin levels, highlighting the complex interplay between hormonal disruptions and early-life stress in the development of schizophrenia.