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Depression, chronic diseases, and decrements in health: results from the World Health Surveys

BACKGROUND Depression is an important public-health problem, and one of the leading causes of disease burden worldwide. Depression is often comorbid with other chronic diseases and can worsen their associated health outcomes. Few studies have explored the effect of depression, alone or as a comorbidity, on overall health status. METHODS The WHO World Health Survey (WHS) studied adults aged 18 years and older to obtain data for health, health-related outcomes, and their determinants. Prevalence of depression in respondents based on ICD-10 criteria was estimated. Prevalence values for four chronic physical diseases--angina, arthritis, asthma, and diabetes--were also estimated using algorithms derived via a Diagnostic Item Probability Study. Mean health scores were constructed using factor analysis and compared across different disease states and demographic variables. The relation of these disease states to mean health scores was determined through regression modelling. FINDINGS Observations were available for 245 404 participants from 60 countries in all regions of the world. Overall, 1-year prevalence for ICD-10 depressive episode alone was 3.2% (95% CI 3.0-3.5); for angina 4.5% (4.3-4.8); for arthritis 4.1% (3.8-4.3); for asthma 3.3% (2.9-3.6); and for diabetes 2.0% (1.8-2.2). An average of between 9.3% and 23.0% of participants with one or more chronic physical disease had comorbid depression. This result was significantly higher than the likelihood of having depression in the absence of a chronic physical disease (p<0.0001). After adjustment for socioeconomic factors and health conditions, depression had the largest effect on worsening mean health scores compared with the other chronic conditions. Consistently across countries and different demographic characteristics, respondents with depression comorbid with one or more chronic diseases had the worst health scores of all the disease states. INTERPRETATION Depression produces the greatest decrement in health compared with the chronic diseases angina, arthritis, asthma, and diabetes. The comorbid state of depression incrementally worsens health compared with depression alone, with any of the chronic diseases alone, and with any combination of chronic diseases without depression. These results indicate the urgency of addressing depression as a public-health priority to reduce disease burden and disability, and to improve the overall health of populations.

ICF linking rules : an update based on lessons learned

OBJECTIVE Outcome research seeks to understand the end results of health services. Researchers use a wide variety of outcome measures including technical, clinical and patient-oriented measures. The International Classification of Functioning, Disability and Health (ICF) as a common reference framework for functioning may contribute to improved outcome research. The objective of this paper is to provide an updated version of the linking rules published in 2002 and illustrate how these rules are applied to link technical and clinical measures, health-status measures and interventions to the ICF. RESULTS Three specific linking rules have been established to link health-status measures to the ICF and one specific linking rule has been created to link technical and clinical measures and interventions. A total of 8 linking rules have been established for use with all different outcome measures and with interventions. CONCLUSION The newly updated linking rules will allow researchers systematically to link and compare meaningful concepts contained in them. This should prove extremely useful in selecting the most appropriate outcome measures among a number of candidate measures for the applied interventions. Further possible applications are the operationalization of concrete ICF categories using specific measures or the creation of ICF category-based item bankings.

Childhood adversities and adult psychopathology in the WHO World Mental Health Surveys

BACKGROUND Although significant associations of childhood adversities with adult mental disorders are widely documented, most studies focus on single childhood adversities predicting single disorders. AIMS To examine joint associations of 12 childhood adversities with first onset of 20 DSM-IV disorders in World Mental Health (WMH) Surveys in 21 countries. METHOD Nationally or regionally representative surveys of 51 945 adults assessed childhood adversities and lifetime DSM-IV disorders with the WHO Composite International Diagnostic Interview (CIDI). RESULTS Childhood adversities were highly prevalent and interrelated. Childhood adversities associated with maladaptive family functioning (e.g. parental mental illness, child abuse, neglect) were the strongest predictors of disorders. Co-occurring childhood adversities associated with maladaptive family functioning had significant subadditive predictive associations and little specificity across disorders. Childhood adversities account for 29.8% of all disorders across countries. CONCLUSIONS Childhood adversities have strong associations with all classes of disorders at all life-course stages in all groups of WMH countries. Long-term associations imply the existence of as-yet undetermined mediators.

The stability of the factor structure of the General Health Questionnaire.

BACKGROUND Different versions of the General Health Questionnaire (GHQ), including the GHQ-12 and GHQ-28 have been subjected to factor analysis in a variety of countries. The World Health Organization study of psychological disorders in general health care offered the opportunity to investigate the factor structure of both GHQ versions in 15 different centres. METHODS The factor structures of the GHQ-12 and GHQ-28 extracted by principal component analysis were compared in participating centres. The GHQ-12 was completed by 26,120 patients and 5,273 patients completed the GHQ-28. The factor structure of the GHQ-28 found in Manchester in this study was compared with that found in the earlier study in 1979. RESULTS For the GHQ-12, substantial factor variation between centres was found. After rotation, two factors expressing depression and social dysfunction could be identified. For the GHQ-28, factor variance was less. In general, the original C (social dysfunction) and D (depression) scales of the GHQ-28 were more stable than the A (somatic symptoms) and B (anxiety) scales. Multiple cross-loadings occurred in both versions of the GHQ suggesting correlation of the extracted factors. In Manchester, the factor structure of the GHQ had changed since its development. Validity as a case detector was not affected by factor variance. CONCLUSIONS These findings confirm that despite factor variation for the GHQ-12, two domains, depression and social dysfunction, appear across the 15 centres. In the scaled GHQ-28, two of the scales were remarkably robust between the centres. The cross-correlation between the other two subscales, probably reflects the strength of the relationship between anxiety and somatic symptoms existing in different locations.

WHO Study on the reliability and validity of the alcohol and drug use disorder instruments: overview of methods and results

The WHO Study on the reliability and validity of the alcohol and drug use disorder instruments in an international study which has taken place in centres in ten countries, aiming to test the reliability and validity of three diagnostic instruments for alcohol and drug use disorders: the Composite International Diagnostic Interview (CIDI), the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and a special version of the Alcohol Use Disorder and Associated Disabilities Interview schedule-alcohol/drug-revised (AUDADIS-ADR). The purpose of the reliability and validity (R&V) study is to further develop the alcohol and drug sections of these instruments so that a range of substance-related diagnoses can be made in a systematic, consistent, and reliable way. The study focuses on new criteria proposed in the tenth revision of the International Classification of Diseases (ICD-10) and the fourth revision of the diagnostic and statistical manual of mental disorders (DSM-IV) for dependence, harmful use and abuse categories for alcohol and psychoactive substance use disorders. A systematic study including a scientifically rigorous measure of reliability (i.e. 1 week test-retest reliability) and validity (i.e. comparison between clinical and non-clinical measures) has been undertaken. Results have yielded useful information on reliability and validity of these instruments at diagnosis, criteria and question level. Overall the diagnostic concordance coefficients (kappa, kappa) were very good for dependence disorders (0.7-0.9), but were somewhat lower for the abuse and harmful use categories. The comparisons among instruments and independent clinical evaluations and debriefing interviews gave important information about possible sources of unreliability, and provided useful clues on the applicability and consistency of nosological concepts across cultures.

The role of Environment in the International Classification of Functioning, Disability and Health (ICF)

Purpose : This paper provides a framework for understanding the impact of environmental factors on functioning when a person has a health condition. This understanding provides the rationale for including environmental factors in WHOs International Classification of Functioning, Disability and Health (ICF). Method and Results : This conceptual paper uses a review format to provide, firstly, an historical perspective on the integration of environmental factors into the understanding of disability and the ICF; secondly, a description of the overall ICF and, specifically, the environmental factors section; and thirdly, an overview of the interaction of a person with a health condition and the environment in which they live, and the outcome of disability. Conclusions : The ICF is a classification that allows a comprehensive and detailed description of a persons experience of disability, including the environmental barriers and facilitators that have an impact on a persons functioning. The recognition of the central role played by environmental factors has changed the locus of the problem and, hence, focus of intervention, from the individual to the environment in which the individual lives. Disability is no longer understood as a feature of the individual, but rather as the outcome of an interaction of the person with a health condition and the environmental factors.

Healthy life expectancy: comparison of OECD countries in 2001

Objectives: To compare average levels of population health for Australia and other OECD countries in 2001.

Nosological comparisons of alcohol and drug diagnoses: a multisite, multi-instrument international study

International nosological research was conducted to determine cross-system agreement on alcohol and drug dependence and harmful use (abuse). ICD-10, DSM-IV and DSM-III-R diagnoses were compared in 1,811 subjects from a variety of treatment and other types of settings from 12 sites around the world. Three diagnostic instruments were used: the Alcohol Use Disorders and Associated Disabilities Interview Schedule-Alcohol/Drug-Revised (AUDADIS-ADR), the composite international diagnostic interview (CIDI), and the schedules for clinical assessment in neuropsychiatry (SCAN). At seven of the study sites, two or more of these instruments were used. Results for dependence diagnoses showed excellent cross-system agreement across sites and instruments, especially for current diagnoses. Cross-system agreement for harmless use (abuse) was much lower and less consistent. Geographic location or culture appeared to have little influence on the results for either dependence or harmful use.

Comments from WHO for the Journal of Rehabilitation Medicine Special Supplement on ICF Core Sets.

Health indicators have traditionally focused on deaths anddiseases. While mortality data or diagnostic data on morbidityare important in their own right, they do not adequately capturehealth outcomes of individuals or populations. Diagnosis alonedoes not explain what patients can do, what they need, what theirprognosis will be and what the cost of treatment will be. To dealwith such questions, the International Classification of Function-ing, Disability and Health (ICF) (1) was developed to provide acommon framework for health outcome measurement. The ICFenables us to capture information about the functioning ofindividuals. What happens when people get ill? What they canand cannot do due to their health condition? What difference dothe treatments make? To answer such questions in a clinicallyrelevant manner and to compare across individuals, treatmentsor over time we need common definitions, anchor points and aconsensus on the conceptual framework.The concept of measuring functioning, disability or health isnot new. There are hundreds of assessment tools. Mostlyclinicians in different specialities have developed condition-specific assessment tools (e.g. Arthritis Impact MeasurementScale, AIMS 2; Hamilton Rating Scale of Depression, HAMD;McGill Pain Assessment Questionnaire, MPQ; OutcomeMeasures in Rheumatology Clinical Trials, OMERACT). Thereare also some generic measures (SF-36, Nottingham HealthProfile, EuroQol-5D). These measures have proven useful totrack outcomes, but they are neither comprehensive nor do theyfully map to the ICF. The result, well-known and muchcriticized, is “data silos” in which assessment data acquired inone episode of care – emergency, medical, rehabilitative, out-patient, and community clinical care – cannot be carried over toanother episode of care involving a different clinical focus. Tocompare outcome data across diseases and interventions weneed a common framework that will serve as a “Rosetta Stone”.The ICF makes it possible to link together these data acrossconditions or interventions, eliminating the frustrating data siloeffect, and making for more efficient, transparent, and cost-effective healthcare.A classification needs to be exhaustive by its very nature andbecomes very complex for daily use unless it is transformed intopractice-friendly tools. For example, a clinician cannot easilytake the main volume of ICF and consistently apply it to his orher patients. In daily practice, clinicians will need only a fractionof the categories found in the ICF. As a general rule, 20% of thecodes will explain 80% of the variance observed in practice.With this need in mind, WHO has already created a series ofinstruments based on the ICF, like the ICF Checklist and theWHO Disability Assessment Schedule II (WHO DAS II) (2).The ICF Checklist is a practical translation of the ICF forclinical practice (3). Items from the classification were chosenby experts to list the most commonly used domains, and laterfield tested to verify the selection and make additions of missingitems. The ICF Checklist gives a thumbnail sketch of the mainfunctioning of any individual in terms of body functions andstructures, activities and participation, and environmentalfactors. On the other hand, the WHO DAS II is an assessmentinstrument that gives a total score of disability based on theactivities and participation domains of the ICF. Both instrumentswere explicitly designed to be generic assessment tools usable ina wide range of applications aiming for data comparabilityacross conditions and interventions. This feature constitutes theprimary strength and virtue of these two instruments.However, the generic character of the ICF Checklist and theWHO DAS II may be a drawback in specialty settings. Forexample, a clinician dealing with patients with arthritis will needa wider range of categories to identify functions in theneuromusculoskeletal and movement-related area. A speechand language therapist, on the other hand, will require detaileddescription of voice and speech functions and related structures.This is the dilemma: on the one hand we need a “common base”to compare with other health conditions and interventions; onthe other hand we need “variability” to capture the detail todescribe the profile of a unique group. For such specializedclinical settings, “one (generic) size does not fit all” and the“devil is in the detail”.This obvious clinical requirement has been the primarymotivation for WHO in collaboration with the Department ofPhysical Medicine and Rehabilitation and the newly establishedICF Research Branch of the WHO FIC CC (DIMDI), IMBK atthe Ludwig Maximilian University Munich to develop ICF CoreSets (4). The ICF Core Sets have “common” categories that willhelp to address the comparability issue. These commoncategories are comparable to the generic ICF Checklist. TheICF Core Sets have “additional items” that give a more detailedpicture for 12 chosen clinical conditions. The papers presentedin this volume describe in detail the rigorous scientific processby which these 12 condition specific ICF Core Sets havebeen developed. Interestingly, the papers show not only the

Identification of candidate categories of the International Classification of Functioning Disability and Health (ICF) for a Generic ICF Core Set based on regression modelling

BackgroundThe International Classification of Functioning, Disability and Health (ICF) is the framework developed by WHO to describe functioning and disability at both the individual and population levels.While condition-specific ICF Core Sets are useful, a Generic ICF Core Set is needed to describe and compare problems in functioning across health conditions.MethodsThe aims of the multi-centre, cross-sectional study presented here were: a) to propose a method to select ICF categories when a large amount of ICF-based data have to be handled, and b) to identify candidate ICF categories for a Generic ICF Core Set by examining their explanatory power in relation to item one of the SF-36.The data were collected from 1039 patients using the ICF checklist, the SF-36 and a Comorbidity Questionnaire.ICF categories to be entered in an initial regression model were selected following systematic steps in accordance with the ICF structure. Based on an initial regression model, additional models were designed by systematically substituting the ICF categories included in it with ICF categories with which they were highly correlated.ResultsFourteen different regression models were performed. The variance the performed models account for ranged from 22.27% to 24.0%. The ICF category that explained the highest amount of variance in all the models was sensation of pain. In total, thirteen candidate ICF categories for a Generic ICF Core Set were proposed.ConclusionThe selection strategy based on the ICF structure and the examination of the best possible alternative models does not provide a final answer about which ICF categories must be considered, but leads to a selection of suitable candidates which needs further consideration and comparison with the results of other selection strategies in developing a Generic ICF Core Set.