Measuring depression as a short-term state and as a trait: multilevel approach

Magdalena Szwed Doctoral School of Social Sciences, Maria Curie-Sklodowska University in Lublin, Poland https://orcid.org/0009-0005-5156-680X Oleg Gorbaniuk 1. Institute of Psychology, Maria Curie-Sklodowska University in Lublin, Poland; 2. Department of Psychology, Casimir Pulaski Radom University, Poland https://orcid.org/0000-0001-9830-8537 Julia Buglińska Fundacja Niepodzielni https://orcid.org/0009-0002-3278-8704 Weronika Boreczek Paderewski International Primary School in Lublin, Poland https://orcid.org/0009-0006-5489-3360 Mateusz Mazur iGaming Dragon https://orcid.org/0009-0003-1388-9558 DOI: https://doi.org/10.12923/2353-8627/2025-0006 Introduction: The Whole Trait Theory allows to conceptualise constructs as a short-term state and as a trait. Depression also can be understood in two ways as a short-term state and as a trait. The aim of the presented study was to verify the factor structure of depression scale at both the inter- and intra-individual levels and to examine the correlation between the density of depression state and depression as a trait. Material and methods: The study used the depression scale from the DASS-21, and conducted a diary study that lasted 14 days and was based on repeated measurements on a sample of 147 people (49.3% female, 50.7% male). The research was conducted as an online survey, with items displayed in random sequence for each person every day. Respondents reported daily on the intensity of their experience of depression. Results: A two-level confirmatory factor analysis proved that single-factor structures are the best way to explain the inter- and intra-individual variance of depression. The congeneric reliability for the measurement of depression as a state and as a density of states was high. The correlation between the average measurement of depression as a state and a single measurement of depression as a trait was very strong, thus providing empirical evidence of the Whole Trait Theory. Conclusions: The present study opens new possibilities for measuring depression in research and clinical practice using repeated measurements of depression as a state. The study of the dynamics of changes in depression states allows for more precise prediction of a person's tendency to experience depression. Keywords: depression, state, trait, DASS-21, multilevel approach