Use this URL to cite or link to this record in EThOS:
Title: Elucidating heterogeneity in depression symptom indicators using data from a large, nationally representative U.S. survey
Author: Carragher, Natacha
ISNI:       0000 0001 3521 3362
Awarding Body: University of Ulster
Current Institution: Ulster University
Date of Award: 2008
Availability of Full Text:
Access from EThOS:
Depression is a complex, heterogeneous condition. Attempts to reduce heterogeneity through subtyping have been a long-standing endeavour amongst theorists and clinicians. Subtyping holds promise for guiding research on etiology; better informing clinical management by improving diagnostic practices and prevention approaches; and, yielding tailored treatment strategies. This thesis developed a latent variable modelling framework to elucidate heterogeneity in depression utilising data from the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). As a precursor to investigating heterogeneity, the psychometric properties of the DSM-IV criteria for major depression were evaluated. Confirmatory factor analysis indicated that the criteria mapped unto a unidimensional factor structure. Item response theory analyses suggested that the criteria displayed moderate to strong discrimination, though under-sampled the moderate and severe ranges ofdepressive pathology. Latent class analysis identified four depressive subtypes, labelled severely depressed, psychosomatic, cognitive-emotional, and non-depressed. The typology shares common features with extant subtypes and was validated utilising established covariates of depression. To extend the heterogeneity investigation, differences in the health-related quality of life (HRQoL) evaluations of the subtypes were evaluated. Relative to the non-depressed subtype, the severely depressed, psychosomatic and cognitive-emotional subtypes reported statistically significant lower mental health. The severely depressed subtype reported statistically significant lower physical health relative to the non-depressed subtype. To provide a comprehensive investigation of HRQoL differences, variations in HRQoL evaluations as a function of social, economic, and cultural factors were subsequently examined. In light ofthe public and clinical health significance of major depression, treatment utilisation is an issue of great importance. Based on the severely depressed subtype, three latent classes of treatment utilisation for major depression were empirically identified and validated; these were labelled highly active treatment-seeking, partially active treatment-seeking, and inactive trealment-seeking. The implications of the above findings for research and practice are discussed herein.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available