Phillip Khong

Background/Objectives: This pilot study aimed to investigate the relationship between salivary neuropeptides levels, adverse childhood experiences (ACEs), and altruism in a sample of medical students. Additionally, the study examined potential sex differences in these relationships. Methods: Sixty medical students (36.6% men, 63.3% women) provided saliva samples to measure oxytocin, α-MSH, β-endorphin, neurotensin, and substance P using a custom 5-plex human peptide assay. Participants completed the ACE Survey and Compassionate Love Scale for Humanity (CLS-H) Altruism Survey. Descriptive statistics characterized demographics and survey data, with out-of-range values adjusted to the standard curve maximum. Data normality was assessed with the Jarque–Bera test; due to non-normality, values were log-transformed. Differences between male and female salivary, ACE score, and CLS-H altruism score were tested using t-tests and Mann–Whitney U-tests, while correlations were evaluated with Pearson and Spearman coefficients. Results: The five neuropeptides, while highly correlated with each other, did not exhibit significant relationships with altruism, as measured by the CLS-H Altruism Survey. Finally, female participants demonstrated greater altruistic tendencies compared with male participants with marginal significance. Conclusions: While there were no significant relationships between the fives neuropeptides, ACEs, or altruism; women demonstrated higher levels of altruism compared with men. The data reported in this pilot study did not strongly support the conclusion that neuropeptides influence social behavior and trauma response. Furthermore, future studies with larger, more diverse samples and multiple time point measurements of neuropeptides could be beneficial to better understand the relationships between neuropeptides and any potential implications for mental health interventions.