Self-medication and psychological symptoms among undergraduate health science students: exploratory associations with religiousness and spirituality in a cross-sectional study

Undergraduate health science students experience academic, clinical, and social demands that may affect psychological well-being and influence self-care practices, including self-medication. Religiousness and spirituality may be associated with how students experience and interpret psychological distress, although the direction and independence of these associations remain uncertain. This study aimed to estimate the prevalence of self-medication and compare anxiety and depressive symptom scores across undergraduate programs; associations with sociodemographic, academic, clinical, and religious/spiritual variables were treated as secondary, exploratory analyses given the cross-sectional design and non-probabilistic sampling. This cross-sectional analytical observational study, conducted between May and December 2025, included 163 Dentistry, Psychology, and Nursing students from a private higher education institution in Jundiai, Sao Paulo, Brazil. Participants completed a sociodemographic questionnaire, a structured self-medication questionnaire, the Beck Anxiety Inventory (BAI), the Beck Depression Inventory-II (BDI-II), and the Brief Multidimensional Measure of Religiousness/Spirituality. Because one BAI item was structurally absent from the electronic dataset, the 20 administered BAI items were prorated to the conventional 0–63 metric; this limitation is reported explicitly. Multivariable Poisson regression with robust variance estimated adjusted prevalence ratios for self-medication outcomes, and multivariable linear regression with HC3 robust standard errors estimated adjusted coefficients for anxiety and depression. Final complete-case samples were n = 162 for each Poisson model, n = 159 for anxiety, and n = 150 for depression. Linear-model diagnostics included VIFs, residual assessment, leverage, Cook’s distance, and heteroscedasticity testing. The mean age was 30.0 years (SD 11.7; median 27; IQR 20–39; range 18–68; n = 162). Lifetime self-medication was reported by 132 students (81.0%; 95% CI 74.1–86.7%) and self-medication in the previous 30 days by 112 (68.7%; 95% CI 61.0-75.7%). Stress-related self-medication was uncommon ( n = 9; 5.5%; 95% CI 2.6–10.2%). Anxiety scores differed across programs in the unadjusted comparison (Kruskal-Wallis p = 0.036), driven by Dentistry versus Nursing after Bonferroni correction (adjusted p = 0.043), whereas depression scores did not differ by program ( p = 0.088). Undergraduate program was not associated with either psychological outcome after multivariable adjustment. In the main anxiety model, living with parents (B = 5.28; 95% CI 0.57–9.99; p = 0.028) and current psychiatric medication use (B = 12.14; 95% CI 3.50-20.77; p = 0.006) were associated with higher scores, although both estimates attenuated in influence sensitivity analysis. In the depression model, male sex (B = -7.01; 95% CI -10.20 to -3.82; p < 0.001), non-White self-reported race/skin color (B = 4.21; 95% CI 1.45–6.98; p = 0.003), current psychiatric medication use (B = 11.05; 95% CI 3.51–18.59; p = 0.004), age (B = -0.16; 95% CI -0.29 to -0.02; p = 0.025), and self-rated spirituality (B = -3.21; 95% CI -5.99 to -0.43; p = 0.024) were associated with depression scores. Self-rated religiousness was not independently associated with depression. Diagnostics showed no problematic multicollinearity, but heteroscedasticity and a small number of influential observations supported HC3 inference and cautious interpretation. Self-medication was frequent among undergraduate health science students. Program-level differences were not supported after adjustment. Several psychological associations were identified in the adjusted models, but the anxiety model was sensitive to influential observations and all findings remain cross-sectional and exploratory. The inverse adjusted association between self-rated spirituality and depressive symptoms should not be interpreted as evidence of a protective or causal effect. University-based strategies should integrate mental-health promotion, rational medicine-use education, and accessible student support. Longitudinal, multicenter studies using complete validated instruments and prespecified analyses are needed.