Abstract
Background: Depression is one of the most prevalent and functionally disabling mental health conditions worldwide, with significant personal, social, and economic consequences. Blood group, as a constitutive biological marker, has been theorized to correlate with personality traits and psychological conditions; however, empirical evidence for such an association remains limited and inconsistent, particularly within South Asian clinical populations.
Objective: The present study aimed to examine the relationship between ABO blood group classification and depression severity among clinically diagnosed emerging adults and adults. Additionally, the influence of demographic variables—namely, gender and age—on depression was explored.
Method: A cross-sectional research design was employed. Using a convenient sampling technique, a total of 240 clinically diagnosed depression patients (males = 115; females = 125), aged 18–29 years, were recruited from multiple hospitals in Multan, Pakistan. The Urdu-validated version of the Patient Health Questionnaire-9 (PHQ-9; Kroenke & Spitzer, 2002) was administered alongside a structured demographic information sheet. Data were analyzed using one-way ANOVA, independent samples t-test, and Pearson product-moment correlation. Results: One-way ANOVA revealed no statistically significant variation in PHQ-9 scores across the eight blood group categories (F[7, 232] = 0.279, p = .962). However, independent samples t-test demonstrated a significant gender difference in depression severity (t[238] = −8.50, p < .001), with females exhibiting markedly higher scores than males (M = 16.70 vs. M = 12.82). Pearson correlation revealed a significant negative association between age and depression scores (r = −.242, p < .05).
Conclusion: ABO blood group does not predict depression severity within this clinical sample. Gender and age, however, are significant demographic correlates of depressive symptomatology, consistent with established epidemiological literature.