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Reliability and validity of the Portuguese version of the Generalized Anxiety Disorder (GAD-7) scale
Open accessAbstract
BACKGROUND: Generalized anxiety disorder has a strong impact on health-related quality of life. For this reason, it seems relevant to develop strategies allowing early diagnoses in order to promote appropriate treatments. The objective of this study was to culturally adapt and validate the GAD-7 for the Portuguese patients with generalized anxiety disorder. METHODS: For the cultural adaptation of the Portuguese version of the GAD-7 scale we started with a previous translation made by Mapi Institute and decided to perform a clinical review followed by a cognitive debriefing with patients. Once piloted, this version was then tested in a larger sample for feasibility and reliability (1-week test-retest). Construct validity was assessed by the relationship between GAD-7 and socio-demographic and clinical variables. Its unidimensionality was tested by principal component factor analysis. Criterion validity was assessed by comparing GAD-7 scores with those obtained by HADS, and EQ-5D. STAI was mainly used as a screening indicator for patient inclusion. RESULTS: GAD-7 was considered feasible with a mean completion time of 2.3 minutes and no major floor or ceiling effects. We found an excellent Cronbach's alpha internal consistency score (0.880) and the test-retest and interclass correlation coefficients were also very good. Regarding the construct validity, younger patients, those with higher education, employed and without anxiety symptoms revealed lower GAD-7 scores, meaning better health. The unidimensionality of GAD-7 index was also confirmed by principal component factor analysis. At last, GAD-7 was significantly correlated with other health outcome indices and the classification levels created by it and by HADS showed to be dependent. CONCLUSION: The excellent metric properties confirmed the cultural adaptation and validity of GAD-7 into Portuguese population, allowing the clinicians an early detection and treatment of these patients.
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“The Patient Health Questionnaire (PHQ-9) (Torres et al., 2016) and Generalized Anxiety Disorder Scale (GAD-7) (Sousa et al., 2015) will be used to measure anxiety and depression, respectively, throughout the study.”
From A guided internet-delivered individually-tailored ACT-influenced cognitive behavioural intervention to improve psychosocial outcomes in breast cancer survivors (iNNOVBC): Study protocol (2019) · cites this paper as Sousa et al., 2015
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Validation of the Generalized Anxiety Disorder-7 (GAD-7) among Chinese people with epilepsy
Tong, X., An, D., McGonigal, A., Park, S.-P., & Zhou, D. (2016) · Epilepsy Research · doi:10.1016/j.eplepsyres.2015.11.019 · Cited by 525
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Quality of life under the COVID-19 quarantine
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Metadata
- Authors
- Sousa, T. V., Viveiros, V., Chai, M. V., Vicente, F. L., Jesus, G., Carnot, M. J., Gordo, A. C., & Ferreira, P. L.
- Affiliations
- Pfizer (Portugal) (PT)
- University of Coimbra (PT)
- Corresponding author
- Ferreira, Pedro L
- Venue
- Health and Quality of Life Outcomes
- Published
- 2015-04-25
- Volume
- 13
- Issue
- 1
- Pages
- 50-50
- ISSN
- 1477-7525 (ISSN-L)
- PMC
- PMC4424548
- OpenAlex
- W2116817969
- Cited by
- 237
- References
- 41
- Citations by year
- 2026: 23 · 2025: 36 · 2024: 34 · 2023: 41 · 2022: 30 · 2021: 28 · 2020: 21 · 2019: 12 · 2018: 3 · 2017: 7 · 2016: 1 · 2015: 1
- FWCI
- 6.04
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Locations
- Health and Quality of Life Outcomes (publishedVersion, cc-by)
- Europe PMC (PubMed Central) (publishedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- Portuguese National Funding Agency for Science, Research and Technology (RCAAP Project by FCT) (submittedVersion, other-oa)
- Funders
- Pfizer
- Topics
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Anxiety, Depression, Psychometrics, Treatment, Cognitive Processes
- Social Sciences › Decision Sciences › Management Science and Operations Research › Psychometric Methodologies and Testing
- Health Sciences › Nursing › Research and Theory › Health Education and Validation
- Keywords
- Generalized Anxiety Disorder-7, GAD-7, generalized anxiety disorder, Portuguese translation, cultural adaptation, psychometric validation, test-retest reliability, construct validity, criterion validity, unidimensionality, early diagnosis, health-related quality of life
- MeSH terms
- Adult, Aged, Anxiety, Anxiety Disorders, Diagnosis, Differential, Female, Humans, Male, Middle Aged, Portugal, Psychiatric Status Rating Scales, Psychometrics, Quality of Life, Socioeconomic Factors, Reproducibility of Results, Principal Component Analysis
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