The varying burden of depressive symptoms across adulthood: Results from six NHANES cohorts.

BACKGROUND: Depressive symptoms differ from each other in the degree of functional impairment they cause. The incidence of depression varies across the adult lifespan. We examined whether age moderates the impairment caused by depressive symptoms. METHODS: The study sample (n = 21,056) was adults drawn from six multistage probability samples from the National Health and Nutrition Examination Survey series (NHANES, years 2005-2016) conducted in the United States using cross-sectional, representative cohorts. Depressive symptoms were assessed with the nine-item Patient Health Questionnaire (PHQ-9). We used regression models to predict high functional impairment, while controlling for sociodemographic variables and physical disorders. RESULTS: Age moderated the association between depressive symptoms and functional impairment: middle-aged adults perceived moderate and severe symptoms as more impairing than did others. Older adults reported slightly higher impairment due to mild symptoms. The individual symptoms of low mood, feelings of worthlessness and guilt, and concentration difficulties were more strongly related to high impairment in mid-adulthood as compared to early and late adulthood. LIMITATIONS: Cross-sectional data allows only between-person comparisons. The PHQ-9 is brief and joins compound symptoms into single items. There was no information available concerning comorbid mental disorders. Co-occurring physical disorders were self-reported. CONCLUSIONS: Symptoms of depression may imply varying levels of impairment at different ages. The results suggest a need for age adjustments when estimating the functional impact of depression in the general population. Additionally, they show a need for more accurate assessments of depression-related impairment at older ages. Evidence-based programs may generally benefit from symptom- and age-specific findings.

Symptom severity and disability in psychiatric disorders: The U.S. Collaborative Psychiatric Epidemiology Survey.

BACKGROUND: While most psychiatric diagnoses are based on simple counts of symptoms, some symptoms may be sign of a more severe mental syndrome than others. This calls for validated estimates of the relative severity specific symptoms imply within a disorder. We focused on four diagnostic disorders: Manic Episode (ME), Major Depressive Episode (MDE), Post-traumatic Stress Disorder (PTSD) and Generalized Anxiety Disorder (GAD). Symptom-specific severity parameters were estimated, and validated by examining their association with levels of self-reported disability in daily activities over and above the number of symptoms. METHODS: Data from the cohort study of the U.S. Collaborative Psychiatric Epidemiology Surveys (CPES) was used, which comprises the National Comorbidity Survey Replication, National Survey of American Life, and the National Latino and Asian American Study. The four analytic datasets included respondents who endorsed disorder-specific pre-screening symptoms according to the World Mental Health Survey Initiative's version of the Composite International Diagnostic Interview. Disability was measured using the WHO Disability Assessment Schedule. Item Response Theory and Tobit models were implemented. RESULTS: For ME, PTSD, and GAD (not MDE) symptom severity based on psychometric Item Response Theory predicted disability outcomes after adjusting for symptom count. For PTSD, symptom count was not associated with disability. LIMITATIONS: The analytic sample for each psychiatric disorder was based on a pre-selection stemming from index criteria (e.g. sadness or pleasure loss for MDE), which implies that our results are only generalizable to those individuals at risk rather than for the entire population. Additionally, we acknowledge that the use of unidimensional models is only one of the several options to model psychopathological constructs. CONCLUSIONS: The same number of symptoms may be related to different levels of disability, depending on the specific symptoms from which the person suffers. Diagnostic procedures and treatment decisions may benefit from such additional information without extra costs.

Aproximaciones metodológicas en la investigación nosológica del trastorno por uso de sustancias / Methodological approaches to nosology research in substance use disorders

Introducción. La investigación sobre los fundamentos teóricos de los trastornos por consumo de sustancias se está incrementando en los últimos años. La aplicación de nuevos modelos estadísticos y psicométricos están aportando nuevas formas de conceptualizar dichos trastornos. Objetivo. El objetivo de este trabajo es ofrecer los principales resultados que se obtienen tras la aplicación de estos modelos a los trastornos por consumo de sustancias. Método. Se realizó una revisión de artículos en PubMed y PsycInfo, con finalización en el mes de marzo de 2012. Los términos de búsqueda fueron "nosology" "dimensionality", "factorial structure", combinados con las diferentes drogas. Resultados. Los estudios cuestionan el sistema categorial de diagnóstico, reconociendo la existencia de diferentes perfiles. Por otro lado, las evidencias empíricas apoyan la creación de un trastorno por consumo de sustancias, en el que se incluyen los criterios de abuso y dependencia. Conclusiones. Las evidencias empíricas obtenidas apoyan la introducción de modificaciones en el proceso diagnóstico de los trastornos por uso de sustancias. Tales modificaciones, en cierta medida recogidas para el DSM-V, deben contemplar también su aplicabilidad en el ámbito clínico (AU)

Introduction. Research on nosology of substance use disorders has been increased in recent years. New statistical and psychometric models are providing new ways to understand these disorders. Objective. The aim of this work is providing the main results from a review concerning the application of these models to Substance Use Disorders. Method. A review was conducted in PubMed and PsycInfo with completion in March 2012. Keywords used: 'nosology', 'dimensionality' and 'factorial structure' with different substances. Results. Studies challenge the categorical system for diagnosis, recognizing the existence of different severity profiles. Moreover, the empirical evidence supports a continuum of substance use disorders, whit abuse and dependence criteria included. Conclusions. Empirical evidence supports modifications in the diagnosis process of Substance Use Disorders for DSM-V. Such changes should also be considered regarding to their applicability in the clinical setting (AU)