Why GHQ threshold varies from one place to another.

BACKGROUND: No convincing explanation has been forthcoming for the variation in best threshold to adopt for the GHQ in different settings. METHODS: Data dealing with the GHQ and the CIDI in 15 cities from a recent WHO study was subjected to further analysis. RESULTS: The mean number of CIDI symptoms for those with single diagnoses, or those with multiple diagnoses, does not vary between cities. However, the best threshold is found to be related to the prevalence both of single and of multiple diagnoses in a centre. Variations in the diagnoses to be included in the 'gold standard' did not account for the variation observed. There was a strong relationship between area under the ROC curve (as a measure of the discriminatory power of the GHQ) and the best threshold, with higher thresholds being associated with superior performance of the GHQ. The items on the GHQ-12 that provided most discrimination between cases and non-cases varied from one centre to another. CONCLUSIONS: The GHQ threshold is partly determined by the prevalence of multiple diagnoses, with higher thresholds being associated by higher rates of both single and multiple diagnosis. The mean GHQ score for the whole population of respondents provides a rough guide to the best threshold. In those centres where the discriminatory power of the GHQ is lowest, it is necessary to use a low threshold as a way of ensuring that sensitivity is protected, but the positive predictive value of the GHQ is then lower. Some of the variation between centres is due to variation in the discriminatory power of different items.

Common mental disorders and disability across cultures. Results from the WHO Collaborative Study on Psychological Problems in General Health Care.

OBJECTIVE: To examine the impact of common mental illness on functional disability and the cross-cultural consistency of this relationship while controlling for physical illness. A secondary objective was to determine the level of disability associated with specific psychiatric disorders. DESIGN: A cross-sectional sample selected by two-stage sampling. SETTING: Primary health care facilities in 14 countries covering most major cultures and languages. PATIENTS: A total of 25,916 consecutive attenders of these facilities were screened for psychopathology using the General Health Questionnaire (96% response). Screened patients were sampled from the General Health Questionnaire score strata for the second-stage Composite International Diagnostic Interview administered to 5447 patients (62% response). MAIN OUTCOME MEASURES: Patient-reported physical disability, number of disability days, and interviewer-rated occupational role functioning. RESULTS: After controlling for physical disease severity, psychopathology was consistently associated with increased disability. Physical disease severity was an independent, although weaker, contributor to disability. A dose-response relationship was found between severity of mental illness and disability. Disability was most prominent among patients with major depression, panic disorder, generalized anxiety, and neurasthenia; disorder-specific differences were modest after controlling for psychiatric comorbidity. Results were consistent across disability measures and across centers. CONCLUSIONS: The consistent relationship of psychopathology and disability indicates the compelling personal and socioeconomic impact of common mental illnesses across cultures. This suggests the importance of impairments of higher-order human capacities (eg, emotion, motivation, and cognition) as determinants of functional disability.

Outcome of depression and anxiety in primary care. A three-wave 3 1/2-year study of psychopathology and disability.

BACKGROUND: We evaluated the long-term outcome of depression and anxiety and associated disability among primary-care attenders with common psychiatric disorders and symptoms (n = 201) using binary and multicategorical, interview-based outcome measures of psychiatric illness and disability. METHODS: A two-stage design was used. In the first stage, 1994 consecutive attenders of 25 general practitioners were screened on psychiatric illness with the General Health Questionnaire and by their physicians. A stratified random sample (n = 292) with differing probabilities was selected for second-stage interview (Present State Examination and Groningen Disability Schedule). Patients with psychiatric symptoms (n = 201) were reassessed 1 (n = 182) and 3 1/2 (n = 154) years later. RESULTS: At 1- and 3 1/2-year follow-ups, many cases no longer met the criteria of their baseline diagnosis and disability levels had substantially dropped. However, partial remission, not full recovery, was the rule, and was associated with residual disability. Depression had better outcomes than anxiety and mixed anxiety-depression. CONCLUSIONS: We concluded that a multicategorical, rather than a binary, outcome measure better reflects patient outcomes, since it highlights partial remission, mild symptoms, and residual disability, and as such, stresses the need to supplement short-term treatment. A multicategorical caseness model may be advantageous for research and clinical practice. We suggest a dynamic-equilibrium model to account for residual symptoms and disability. This study is a follow-up to two earlier reports on the recognition, treatment, and 1-year course of common psychiatric illnesses in general practice.

Depression, anxiety, and social disability show synchrony of change in primary care patients.

OBJECTIVES: The purposes of this study were to (1) characterize the social disability associated with the common psychiatric illnesses of primary care patients in terms of role dysfunction (self-care, family role, social role, occupational role) and (2) establish whether severity of psychiatric illness and disability level show synchrony of change. METHODS: A two-stage sample design was employed. In the first stage, 1994 consecutive attenders of 25 general practitioners were screened on psychiatric illness by their physicians and with the General Health Questionnaire. A stratified random sample (n = 285) with differing probabilities was selected for a second-stage interview. Patients with psychiatric symptoms were reinterviewed 1 and 3.5 years later (n = 143). RESULTS: (1) Disability level among patients was increased (moderately for depression, mildly for anxiety) and was associated with severity of psychiatric illness. (2) Most disability was found in occupational and social roles. (3) Change in severity of psychiatric illness was concordant with change in level of disability and was largely invariant across diagnosis (depression, anxiety, mixed anxiety/depression). At follow-up, disability among improved patients had returned to normal levels. CONCLUSIONS: Psychiatric illness in primary care patients is associated with mild to moderate disability, and severity of psychiatric illness and disability show synchrony of change.