Abstract: OBJECTIVE: The aim of the current study was to examine two major assumptions behind the DSM-IV diagnosis of major depressive episode (MDE): that depression represents a distinct category defined by a valid symptom threshold, and that each depressive symptom contributes equally to the diagnosis. METHODS: Data were from the Australian National Survey of Mental Health and Wellbeing. Participants consisted of a random population-based sample of 10 641 community volunteers, representing a response rate of 78%. DSM-IV diagnoses of MDE and other mental disorders were obtained using the Composite International Diagnostic Interview, version 2.0. Analyses were carried out on the subsample of respondents who endorsed either depressed mood or loss of interest (n =2137). Multivariate linear regression analyses examined the relationship between the number and type of symptoms and four independent measures of impairment. RESULTS: The relationship between the number of depressive symptoms and the four measures of impairment was purely linear. Three individual symptoms (sleep problems, energy loss, and psychomotor disturbance) were all independent predictors of three of the four measures of impairment. CONCLUSIONS: Counting symptoms alone is limited in guiding a clear diagnostic threshold. The differential impact of individual symptoms on impairment suggests that impairment levels may be more accurately estimated by weighting the particular symptoms endorsed.
Abstract: OBJECTIVE: The purpose of this study was to compare a newly developed screening measure of disability, the WHODAS II, to three established generic effectiveness measures in terms of its sensitivity to symptom change in people with anxiety disorders. METHOD: Patients who had undergone treatment for social phobia or panic disorder/agoraphobia at an anxiety disorders clinic were administered generic effectiveness measures and symptom measures before and after treatment. The design was naturalistic and observational. Data analysis included correlations between generic effectiveness and symptom measures; and effect size calculations regarding the ability of each generic effectiveness measure to discriminate between patients whose symptoms improved and patients whose symptoms did not improve over the course of treatment. RESULTS: The WHODAS II was consistently the most sensitive generic effectiveness measure in its capacity to detect symptom changes in patients with social phobia. The SF-12 and K-10 also showed moderate sensitivity to symptom change. In the sample of patients with panic disorder/agoraphobia, the SF-12 was the most sensitive measure overall, closely followed by the K-10 and WHODAS II. The NCS Disability Days were the least sensitive to symptom change in both samples. CONCLUSION: The WHODAS II is at least as sensitive as other generic effectiveness measures to anxiety symptom changes, and is particularly sensitive to changes in social anxiety symptoms. It may prove to be a valuable measurement tool for informing public health policy in relation to anxiety disorders.
Abstract: BACKGROUND: Gender differences in the prevalence of post-traumatic stress disorder were examined by analysing discrepancies between the DSM-IV and ICD-10 diagnostic systems. METHOD: Data from the Australian National Survey of Mental Health and Well-Being (n=10641) were analysed at the diagnostic, criterion and symptom level for DSM-IV and ICD-10 PTSD for males versus females. RESULTS: While there was a significant gender difference in the prevalence of PTSD for ICD-10, no such difference was found for DSM-IV. The pattern of gender difference at the diagnostic level was mirrored in the pattern of gender differences at the criterion level for both DSM-IV and ICD-10. Females only endorsed three symptoms at a significantly higher rate than males. For all other symptoms, endorsement was equal. This apparently small gender difference at the symptom level was sufficient to cause the gender difference at the diagnostic level for ICD-10, but not DSM-IV because of the different manner in which symptoms are configured into criteria in each of the diagnostic systems. CONCLUSIONS: Gender differences in ICD-10 PTSD but not in DSM PTSD diagnoses are attributable in this study to different patterns of endorsement of symptoms by males and females. Possible reasons for the differential endorsement of symptoms and implications for the use of epidemiological instruments are discussed.
Abstract: BACKGROUND: Patterns of co-occurrence among the common mental disorders may provide information about underlying dimensions of psychopathology. The aim of the current study was to determine which of four models best fits the pattern of co-occurrence between 10 common DSM-IV and 11 common ICD-10 mental disorders. METHOD: Data were from the Australian National Survey of Mental Health and Well-Being (NSMHWB), a large-scale community epidemiological survey of mental disorders. Participants consisted of a random population-based sample of 10641 community volunteers, representing a response rate of 78%. DSM-IV and ICD-10 mental disorder diagnoses were obtained using the Composite International Diagnostic Interview (CIDI), version 2.0. Confirmatory factor analysis (CFA) was used to assess the relative fit of competing models. RESULTS: A hierarchical three-factor variation of a two-factor model demonstrated the best fit to the correlations among the mental disorders. This model included a distress factor with high loadings on major depression, dysthymia, generalized anxiety disorder (GAD), post-traumatic stress disorder (PTSD) and neurasthenia (ICD-10 only); a fear factor with high loadings on social phobia, panic disorder, agoraphobia and obsessive-compulsive disorder (OCD); and an externalizing factor with high loadings on alcohol and drug dependence. The distress and fear factors were best conceptualized as subfactors of a higher order internalizing factor. CONCLUSIONS: A greater focus on underlying dimensions of distress, fear and externalization is warranted.
Abstract: OBJECTIVE: Relative to other mental disorders, the prevalence of obsessive-compulsive disorder (OCD) in the general population is not well established. Some epidemiological surveys have determined the prevalence of DSM-III OCD, but this is one of the first reports, to the authors' knowledge, of DSM-IV OCD's prevalence. METHOD: Data from the Australian National Survey of Mental Health and Well-Being, a nationally representative epidemiological survey of mental disorders, were analyzed. The prevalence and associated characteristics of DSM-IV OCD were identified, and then the data were rescored for DSM-III OCD. Cases defined by each system were compared. RESULTS: The 12-month prevalence of DSM-IV OCD was 0.6%, considerably less than found in surveys employing DSM-III diagnostic criteria. DSM-IV OCD showed significantly higher levels of comorbidity, disability, health service use, and treatment received. CONCLUSIONS: Changes in the reported prevalence and severity of OCD between DSM-III and DSM-IV cases are most likely a function of the differences in diagnostic criteria between DSM-III and DSM-IV.
Abstract: BACKGROUND: The latent structure of depression was examined using taxometric analysis, a family of statistical procedures designed specifically to test whether a given construct is best conceptualized as a distinct category or a continuous dimension. METHOD: Data were derived from the Australian National Survey of Mental Health and Well-Being, a large epidemiological survey that measured the prevalence of the major DSM-IV and ICD-10 mental disorders. Two taxometric procedures, maximum covariance (MAXCOV) and mean above minus below a cut (MAMBAC), were carried out on a sample of 1933 community volunteers. Simulated categorical and dimensional datasets aided in the interpretation of the research data. RESULTS: The results of the taxometric analyses in the subsample who endorsed at least one symptom of depression were consistent with a dimensional latent structure of depression. CONCLUSIONS: The findings of the current study suggest that depression, as measured in this subsample, is best conceptualized, measured and classified as a continuously distributed syndrome rather than as a discrete diagnostic entity. Incorporation of dimensional measurement into psychiatric classification systems remains a challenge for the future.
Abstract: BACKGROUND: The lack of established brief Personality Disorder (PD) screening instruments may account for the absence of PD data from previous national mental health surveys. This paper documents the measurement of PD in a large Australian survey, with a particular focus on the characteristics of the screening instrument and the consequences of its mode of administration and scoring. METHODS: PD was assessed in the 1997 Australian National Survey of Mental Health and Wellbeing (N=10,641 adults) using the 59-item version of the International Personality Disorder Examination Questionnaire (IPDEQ), which was administered in a computerised format by trained non-clinical interviewers. RESULTS: Normative profiles are reported for three IPDEQ scoring schemes (simple categorical, IPDEQ(S); ICD-10 criterion based categorical, IPDEQ(C); and dimensional scoring, IPDEQ(D)), together with an examination of the IPDEQ's psychometric properties and associations with Axis I comorbidity, disability, and selected psychosocial characteristics. The overall rate of ICD-10 PD in Australia was estimated to be 6.5%, although the categorical assessment of dissocial PD clearly provided an underestimate. PD was associated with younger age, poorer functioning, and a sevenfold increase in the number of comorbid Axis I disorders during the preceding 12 months. CONCLUSIONS: While the methods used to assess PD in the national survey were constrained by project demands, the overall performance of the IPDEQ was considered satisfactory, based on data from a range of sources. In particular, although IPDEQ item and subscale revisions are recommended, evidence is presented suggesting that aggregate IPDEQ dimensional scores should provide useful self-report indices of the overall likelihood of PD.
Abstract: We report population data on DSM-IV Generalized Anxiety Disorder (GAD) from the Australian National Survey of Mental Health and Well-Being, obtained from a nationwide household survey of adults using a stratified multistage sampling process. A response rate of 78.1% resulted in 10,641 persons being interviewed. Diagnoses were made using the Composite International Diagnostic Interview. The interview was computerised and conducted by trained lay interviewers. We investigated comorbidity between GAD and major depressive disorder (MDD). The results indicate that sociodemographic correlates of GAD, and associated disablement and service use, are influenced by the presence of a comorbid depressive disorder but cannot be fully explained by the presence of that disorder. In addition, GAD was confirmed as significantly disabling, even as a single disorder. We conclude that the results are consistent with the view that GAD has a significant and independent impact on the burden of mental disorders.
Abstract: BACKGROUND: There have been few large-scale epidemiological studies which have examined the prevalence of bipolar disorder. The authors report 12-month prevalence data for DSM-IV bipolar disorder from the Australian National Survey of Mental Health and Well-Being. METHOD: The broad methodology of the Australian National Survey has been described previously. Ten thousand, six hundred and forty-one people participated. The 12-month prevalence of euphoric bipolar disorder (I and II)--similar to the euphoric-grandiose syndrome of Kessler and co-workers--was determined. Those so identified were compared with subjects with major depressive disorder and the rest of the sample, on rates of co-morbidity with anxiety and substance use disorders as well as demographic features and measures of disability and service utilization. Polychotomous logistic regression was used to study the relationship between the three samples and these dependent variables. RESULTS: There was a 12-month prevalence of 0-5 % for bipolar disorder. Compared with subjects with major depressive disorder, those with bipolar disorder were distinguished by a more equal gender ratio; a greater likelihood of being widowed, separated or divorced; higher rates of drug abuse or dependence; greater disability as measured by days out of role; increased rates of treatment with medicines; and higher lifetime rates of suicide attempts. CONCLUSIONS: This large national survey highlights the marked functional impairment caused by bipolar disorder, even when compared with major depressive disorder.
Abstract: BACKGROUND: Two new screening scales for psychological distress, the K6 and K10, have been developed but their relative efficiency has not been evaluated in comparison with existing scales. METHOD: The Australian National Survey of Mental Health and Well-Being, a nationally representative household survey, administered the WHO Composite International Diagnostic Interview (CIDI) to assess 30-day DSM-IV disorders. The K6 and K10 were also administered along with the General Health Questionnaire (GHQ-12), the current de facto standard of mental health screening. Performance of the three screening scales in detecting CIDI/DSM-IV mood and anxiety disorders was assessed by calculating the areas under receiver operating characteristic curves (AUCs). Stratum-Specific Likelihood Ratios (SSLRs) were computed to help produce individual-level predicted probabilities of being a case from screening scale scores in other samples. RESULTS: The K10 was marginally better than the K6 in screening for CIDI/DSM-IV mood and anxiety disorders (K10 AUC: 0.90, 95%CI: 0.89-0.91 versus K6 AUC: 0.89, 95%CI: 0.88-0.90), while both were significantly better than the GHQ-12 (AUC: 0.80, 95%CI: 0.78-0.82). The SSLRs of the K10 and K6 were more informative in ruling in or out the target disorders than those of the GHQ-12 at both ends of the population spectrum. The K6 was more robust than the K10 to subsample variation. CONCLUSIONS: While the K10 might outperform the K6 in screening for severe disorders, the K6 is preferred in screening for any DSM-IV mood or anxiety disorder because of its brevity and consistency across subsamples. Precision of individual-level prediction is greatly improved by using polychotomous rather than dichotomous classification.
Abstract: BACKGROUND: This article reports data on social phobia from the first large scale Australian epidemiological study. Prevalence rates, demographic correlates and co-morbidity in the sample that met criteria for social phobia are reported and gender differences examined. METHOD: Data were obtained from a stratified sample of 10641 participants as part of the Australian National Survey of Mental Health and Well-Being (NSMHWB). A modified version of the Composite International Diagnostic Interview (CIDI) was used to determine the presence of social phobia, as well as other DSM-IV anxiety, affective and substance use disorders. The interview also screened for the presence of nine ICD-10 personality disorders, including anxious personality disorder, the equivalent of DSM-IV avoidant personality disorder (APD). RESULTS: The estimated 12 month prevalence of social phobia was 2.3%, lower than rates reported in several recent nationally representative epidemiological surveys and closer to those reported in the Epidemiological Catchment Area study (ECA) and other DSM-III studies. Considerable co-morbidity was identified. Data indicated that the co-morbidity with depression and alcohol abuse and dependence were generally subsequent to onset of social phobia and that the additional diagnosis of APD was associated with a greater burden of affective disorder. Social phobia most often preceded major depression, alcohol abuse and generalized anxiety disorder. CONCLUSIONS: Social phobia is a highly prevalent, highly co-morbid disorder in the Australian community. Individuals with social phobia who also screen positively for APD appear to be at greater risk of co-morbidity with all surveyed disorders except alcohol abuse or dependence.
Abstract: BACKGROUND: Community surveys have reported prevalence of depressive disorders in adult populations since the 1970s. Until recently, no epidemiological studies of the same magnitude have been conducted to provide a profile of the adult population in Australia. This study examines the current (30-day) prevalence and correlates of major depression in the adult Australian population using data from the National Survey of Mental Health and Well-being, and compares the results with other national studies. METHODS: Data were derived from a national sample of 10,641 people 18-75+ years of age surveyed using the computerised version of the Composite International Diagnostic Interview Version 2.1. RESULTS: The overall weighted prevalence of current (30-day) major depression was 3.2% with the highest rate (5.2%) being found in females in mid life. This rate is between those of the USA National Comorbidity Survey and the Epidemiological Catchment Area study, and similar to the British Psychiatric Morbidity Survey. The strongest correlates for reported current major depression include being unemployed, smoking, having a medical condition, followed by being in mid life, previously married, and female. Living with a partner and drinking 1 to 2 glasses of alcohol per day were least correlated. Some correlates of major depression relate to social disadvantage and lifestyle issues. LIMITATIONS: The study design does not allow definition of direction of causality. CONCLUSION: Lowering the prevalence rate of major depression will require close attention to public health approaches to address the relationships between smoking, social isolation, poor health, mood and physical well-being. The best focus for this approach may be primary care settings.
Abstract: Used data from the Australian National Mental Health Survey to model the impact of differences between the International Classification of Disease-10 (ICD-10) and the DSM-IV on the diagnosis of generalized anxiety disorder. The results show that the concordance between the current classifications would be improved with the removal of the criterion for uncontrollability from DSM-IV, a closer focus on the symptoms of hypervigilance and scanning as in DSM-IV and the removal of the clinical significance criterion from DSM-IV. Equivalency of the exclusion criteria between the two classification systems reduces the concordance, demonstrating that each classification systems is a set of interdependent diagnoses, and to ultimately achieve concordance, all diagnoses must be considered together. (PsycINFO Database Record (c) 2002 APA, all rights reserved)
Abstract: Comorbidity in epidemiological surveys of mental disorders is common and of uncertain importance. This article explores the correlates of current comorbidity. Data from the Australian National Survey of Mental Health and Well-Being (N=10,641) were used to evaluate the relationships between comorbidity, disability and service utilisation associated with particular mental disorders. The number of current comorbid disorders predicted disability, distress, neuroticism score and service utilisation. Comorbidity is more frequent than expected, which might be due to the effect of one disorder on the symptom level of another, or to the action of common causes on both. The combination of affective and anxiety disorders was more predictive of disability and service utilisation than any other two or three group combinations. When people nominated their principal disorder as the set of symptoms that troubled them the most, the affective and anxiety disorders together were associated with four-fifths of the disability and service utilisation. To make clinical interventions more practical, current comorbidity is best reduced to a principal disorder and subsidiary disorders. (PsycINFO Database Record (c) 2002 APA, all rights reserved)
Abstract: Notes that agoraphobia without a history of panic attacks is a disorder lacking strong support. Data from the Australian National Survey (n=10,641) were explored in respect to panic disorder with or without agoraphobia (PDA, PD), and agoraphobia without a history of panic disorder (AG). Panic disorder, agoraphobia, and panic disorder with agoraphobia occurred in 3.5% of the adult population. People with this group of disorders were more likely to be female and more likely to seek help than people with other anxiety disorders. Significant anxiety symptoms and unease about safety when out and about occur in all three disorders. People with the double disorder PDA report more comorbid disorders, are more disabled, and have higher neuroticism scores than people with PD or AG. People with AG are older and consult less than people with PD or PDA. Agoraphobia has been devalued as a cause of human suffering. This idea is wrong. Agoraphobia is as common, comorbid, and disabling as PD, but less disabling than the double disorder of PDA. (PsycINFO Database Record (c) 2002 APA, all rights reserved)
Abstract: BACKGROUND: Exclusion criteria are present in almost all diagnostic categories in both DSM-IV and ICD-10. These exclusion criteria state that one diagnosis is not made if it is 'due to' another disorder. However, there is little empirical evidence demonstrating that the hierarchy imposed by the exclusion criteria is meaningful. The current study examines associations between ten common mental disorder pairs to determine whether they are higher for disorder pairs that are classified in DSM-IV and/or ICD-10 as having a hierarchical relationship, than for those that are not hierarchically related. METHOD: Data were analysed from the Australian National Survey of Mental Health and Wellbeing, a large (N = 10,641) epidemiological survey of mental disorders. Bivariate odds ratios between disorder pairs were calculated from logistic regression analyses. Multivariate odds ratios were also calculated from separate logistic regression analyses in which the sample was restricted to likely positive cases, and co-morbid mental disorders and neuroticism scores were both controlled. RESULTS: The odds ratios between disorder pairs related according to the exclusion criteria were higher than those of unrelated disorders, for both DSM-IV and ICD-10. When constraints were placed on the data to control for the effects of co-morbid disorders and neuroticism the same pattern was evident in DSM-IV, but not in ICD-10 CONCLUSION: The patterns of association between disorder pairs found in the exclusion criteria for DSM-IV appear to more closely mirror the patterns of association found in epidemiological data. While this does not guarantee that the exclusion criteria are valid it is argued that identifying significant associations should be the first step in establishing meaningful exclusion criteria
Abstract: Used data from an epidemiological survey of mental disorders to examine the impact of the Mental Disorders-IV (DSM-IV) diagnostic criterion for clinical significance. It was hypothesized that the addition of the clinical significance criterion would produce a group of people who were significantly more likely to consult for psychiatric help, significantly more likely to receive treatment for their psychiatric problems, and significantly more impaired and distressed. It was also hypothesized that these differences would remain once sociodemographic factors and the presence of comorbid disorders were held constant. Data were taken from the Australian National Survey of Mental Health and Well-Being, which interviewed a total of 10,641 people. Results show that the inclusion of DSM-IV diagnostic criterion for clinical significance has a substantial impact on the prevalence, health service use, and disability of 5 mental disorders (major depression, social phobia, generalized anxiety disorder, obsessive-compulsive disorder, and posttraumatic stress disorder). (PsycINFO Database Record (c) 2002 APA, all rights reserved)
Abstract: Objective: To provide normative data on the Kessler Psychological Distress Scale (K10), a scale that is being increasingly used for clinical and epidemiological purposes. Method: The National Survey of Mental Health and Well-Being was used to provide normative comparative data on symptoms, disability, service utilization and diagnosis for the range of possible K10 scores. Results: The K10 is related in predictable ways to these other measures. Implications: The K10 is suitable to assess morbidity in the population, and may be appropriate for use in clinical practice.
Abstract: Examined prevalence and associated disability of Mental Disorders-IV (DSM-IV) and ICD-10 generalized anxiety disorder (GAD). The Composite International Diagnostic Interview was administered to 10,641 people, and the diagnostic criteria that contributed to discrepancies between DSM-IV an ICD-10 GAD were identified. A multiple linear regression analysis was carried out to determine the strength of the relationship between disability, as measured by the SF-12, and discrepant diagnoses of GAD. The concordance between DSM-IV an ICD-10 GAD was fair. The 2 sources of discrepancy when DSM-IV was positive and ICD-10 was negative resulted from the requirement in ICD-10 that the respondent endorse symptoms of autonomic arousal (ICD-10 criterion B) and the requirement that ICD-10 GAD does not co-occur with panic/agoraphobia, social phobia or obsessive-compulsive disorder. The 2 major sources of discrepancy when ICD-10 was positive and DSM-IV was negative resulted from the requirement in DSM-IV that the worry be excessive and that it causes clinically significant distress or impairment. DSM-only GAD cases had significantly higher levels of disability than ICD-only cases of GAD after controlling for demographic variables and the presence of comorbid psychiatric disorders. (PsycINFO Database Record (c) 2002 APA, all rights reserved)
Abstract: Why does the burden of mental disorders persist in established market economies? There are four possibilities: the burden estimates are wrong; there are no effective treatments; people do not receive treatment; or people do not receive effective treatments. Data from the Australian National Survey of Mental Health and Wellbeing about the two commonest mental disorders, generalized anxiety disorder and depression, have been used in examining these issues. The burden of mental disorders in Australia is third in importance after heart disease and cancer, and anxiety and depressive disorders account for more than half of that burden. The efficacy of treatments for both disorders has been established. However, of those surveyed, 40% with current disorders did not seek treatment in the previous year and only 45% were offered a treatment that could have been beneficial. Treatment was not predictive of disorders that remitted during the year. The burden therefore persists for two reasons: too many people do not seek treatment and, when they do, efficacious treatments are not always used effectively
Abstract: The assumption that participants receiving an International Classification of Diseases (ICD)-10 diagnosis of posttraumatic stress disorder (PTSD) will also receive a Mental Disorders-IV (DSM-IV) diagnosis of PTSD was tested. Data were gathered for 1,364 participants (aged 18-88 yrs) using the Composite International Diagnostic Interview (CIDI). The 12-mo prevalence of PTSD was 3% for DSM-IV and 7% for ICD-10 Diagnostic Criteria for Research (ICD-10-DCR). The agreement between the two systems was fair. 48% of the discrepancies between the systems were accounted for by the additional criterion requiring clinically significant distress or impairment included in DSM-IV. The inclusion of symptoms of general numbing of responsiveness accounted for 18% of the discrepancies. It is concluded that ICD-10-DCR PTSD cannot be assumed to be identical to DSM-IV PTSD. (PsycINFO Database Record (c) 2002 APA, all rights reserved)
Abstract: Compared the International Classification of Diseases (ICD)-10 and Mental Disorders-IV (DSM-IV) classification systems using the Composite International Diagnostic Interview with 1,300-1,500 people drawn from a disorder-enriched population sample combined with a clinic sample, enriched so that the prevalence of any disorder was approximately twice that expected in a true sample of the general population. Results indicated that depression, dysthymia, substance dependence and generalised anxiety disorder all displayed high levels of concordance, a reflection of the similarity in diagnostic criteria. Moderate concordance was found in social phobia, obsessive-compulsive disorder and the 3 panic/agoraphobia disorders. The concordance for posttraumatic stress disorder (PTSD) was 35% with ICD-10 identifying cases at twice the frequency of DSM-IV. The concordance was low for substance use/abuse. Overall, the concordance for any mental disorder was 68%, with the threshold for an ICD-10 disorder being lower than that for a DSM-IV disorder. (PsycINFO Database Record (c) 2002 APA, all rights reserved)
