Abstract
<title>Abstract</title> <p> <bold>Purpose:</bold> This study identified determinants of depression severity in a sample of 322 individuals experiencing homelessness in Barcelona (Spain) and evaluated the presence of effect modification by gender group on the association between risk factors and depression severity. <bold>Methods:</bold> A cross-sectional convenience sample was recruited from January of 2024 to February of 2025 through 14 public and private shelters and day centers in Barcelona. Adult individuals meeting an ETHOS score between 1 and 3 were included in the study and carried out a semi-structured interview. Depression severity was assessed through the Patient’s Health Questionnaire-9 (PHQ-9) score. Associations between health determinants and depression severity, and potential effect modifications by gender were evaluated through multivariate regression models including first order interaction terms. <bold>Results:</bold> Among 322 participants, 111 (34.5%) were females and the median (IQR) PHQ-9 score was 7.0 (3.0-12.0). Low physical activity, lack of protection from heat and cold, bad self-perceived physical health and GAD-7 score were significantly and positively associated with PHQ-9 scores in the total sample. In addition, there were significant positive interactions between female gender and several determinants in the association with depression severity, such as: duration of the homelessness episode, self-perceived mental health, GAD-7 and PMQ-9. <bold>Conclusion:</bold> Results suggest <bold/> that the association between determinants and depression severity is modified by gender. Future public health interventions should be tailored to the needs of specific and vulnerable subgroups, such as women in longer homelessness episodes or suffering from mental health comorbidities. </p>