{"doi":"10.1037/pas0001317","title":"Longitudinal invariance of the Patient Health Questionnaire–9 among patients receiving pharmacotherapy for major depressive disorder: A secondary analysis of clinical trial data.","abstract":"Comparing self-reported symptom scores across time requires longitudinal measurement invariance (LMI), a psychometric property that means the measure is functioning identically across all time points. Despite its prominence as a measure of depression symptom severity in both research and health care, LMI has yet to be firmly established for the Patient Health Questionnaire-9 depression module (PHQ-9), particularly over the course of antidepressant pharmacotherapy. Accordingly, the objective of this study was to assess for LMI of the PHQ-9 during pharmacotherapy for major depressive disorder. This was a secondary analysis of data collected during a randomized controlled trial. A total of 1,944 veterans began antidepressant monotherapy and completed the PHQ-9 six times over 24 weeks of treatment. LMI was assessed using a series of four confirmatory factor analysis models that included all six time points, with estimated parameters increasingly constrained across models to test for different aspects of invariance. Root-mean-square error of approximation of the chi-square difference test values below 0.06 indicated the presence of LMI. Exploratory LMI analyses were also performed for separate sex, age, and race subgroups. Root-mean-square error of approximation of the chi-square difference test showed minimal change in model fits during invariance testing (≤ 0.06 for all steps), supporting full LMI for the PHQ-9. LMI was also supported for all tested veteran subgroups. As such, PHQ-9 sum scores can be compared across extended pharmacotherapy treatment durations. (PsycInfo Database Record (c) 2024 APA, all rights reserved).","journal":"Psychological Assessment","year":2024,"id":480159,"datarank":0.11767382367645585,"base_score":0.6931471805599453,"endowment":0.6931471805599453,"self_citation_contribution":0.10397207708399181,"citation_network_contribution":0.013701746592464033,"self_endowment_contribution":0.10397207708399181,"citer_contribution":0.013701746592464033,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":1,"citers_with_citation_signal":1,"citers_with_endowment":1,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9389,"is_data_producer":true,"deposit_databanks":{"ClinicalTrials.gov":["NCT03170362"]},"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":260541,"name":"Adam R. Kinney","orcid":"0000-0002-8852-7477","position":1,"is_corresponding":false},{"id":491986,"name":"Jeri E. Forster","orcid":"0000-0002-7955-9127","position":2,"is_corresponding":false},{"id":256089,"name":"Kelly A. Stearns‐Yoder","orcid":"0000-0002-6323-6198","position":3,"is_corresponding":false},{"id":1278912,"name":"Julie A. Kittel","orcid":"0000-0002-7911-2990","position":4,"is_corresponding":false},{"id":1319452,"name":"A. E. Wood","orcid":"0000-0002-4398-3225","position":5,"is_corresponding":false},{"id":494404,"name":"David W. Oslin","orcid":"0000-0003-4392-4599","position":6,"is_corresponding":false},{"id":256090,"name":"Lisa A. Brenner","orcid":"0000-0002-2629-214X","position":7,"is_corresponding":false},{"id":957512,"name":"Joseph A. Simonetti","orcid":"0000-0002-1092-160X","position":8,"is_corresponding":false},{"id":876017,"name":"Daniel J. Reis","orcid":"0000-0001-7806-3819","position":0,"is_corresponding":true}],"reference_count":0,"raw_metadata":null,"created_at":"2026-07-19T02:06:58.305365Z","pmid":"38753374","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}