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David Chant

Publications and source records attributed to David Chant.

At least 19 recordsLinked to original sources
PubMed2006

Incidence of schizophrenia does not vary with economic status of the country: evidence from a systematic review.

BACKGROUND: A recent systematic review found that the prevalence of schizophrenia was lower in developing nations compared to developed nations. However, there is a lack of information about the association between economic status and the incidence of schizophrenia. The aim of this study was to examine the association between economic status and the underlying incidence of schizophrenia based on a recently published systematic review of the incidence of schizophrenia. METHODS: The analyses were based on 167 discrete incidence rates from 52 studies. Nations were divided into three categories according to per capita gross national product. Based on these categories, we compared the incidence rates for schizophrenia when adjusted for within-study variation. RESULTS: The median (and 10-90% quantiles) incidence rates per 100,000 persons for Least Developed Countries (three studies), Emerging Economies (nine studies), and Developed Countries (42 studies) were 20.0 (0.4-35.0), 11.0 (5.0-26.0) and 16.0 (8.0-48.0) respectively. There was no significant difference in incidence rates between these groups. CONCLUSIONS: While there is a lack of information on the incidence of schizophrenia in the developing world, there is no evidence to suggest that the incidence of schizophrenia varies by economic status. In light of the evidence that the prevalence of schizophrenia is higher in developed countries, more research is warranted focused on the interaction between economic measures, and the incidence, prevalence and course of schizophrenia.

Developed Countries↗
PubMed2006

The psychometric properties of a psychosis screen in a correctional setting.

Many people who go to gaol are mentally ill. Remandees, prisoner receptions or people in jails have a substantially higher rate of severe mental disorder than other prisoners and the general population. There are no completely satisfactory ways to screen for psychosis and few existing screening questionnaires are available for use in correctional establishments. The Screening Instrument for Psychosis (PS) was developed in the context of the Australian Mental Health Survey: Study of Low Prevalence Disorders. It can help indicate whether a person should be referred to mental health professional for a diagnostic evaluation and possible treatment and/or diversion. We trialled the PS in a high security remand and reception centre. Measures of validity and reliability are reported.

Australia↗
PubMed2006

Labor force activity among Australians with musculoskeletal disorders comorbid with depression and anxiety disorders.

AIM: Musculoskeletal disorders (MSD) are a leading cause of work-related disability. This investigation explored the impact of MSD comorbid with depression and anxiety disorders, on labor force activity. METHODS: The Australian Bureau of Statistics provided confidentialized data files collected from a household sample of 37,580 people. MSD, affective, and anxiety disorders were identified and employment restrictions were assessed at four levels of severity. RESULTS: Anxiety and depression of six months duration was present in 12.1% of people with MSD. Comorbidity magnified the negative impacts of single conditions on labor force activity. Most at risk were people with back problems and comorbid depression, people with arthritis or other MSD and comorbid anxiety, males with MSD and comorbid depression, and females with MSD and comorbid anxiety. CONCLUSIONS: The results suggest that the occupational rehabilitation needs of people with MSD comorbid with depression or anxiety may currently be underestimated.

Adolescent↗
PubMed2006

A comparison of Australian men with psychotic disorders remanded for criminal offences and a community group of psychotic men who have not offended.

BACKGROUND: People remanded into custody by the courts have a substantially higher rate of severe mental disorder than other prisoners and the general population. Knowledge of their prevalence, needs and characteristics and an analysis of pathways to care may be necessary to provide mental health care effectively and efficiently. Previous prison studies focusing on psychotic offenders have suffered from the use of instruments not validated in a forensic setting and lack of a relevant comparison group. METHOD: The Diagnostic Interview for Psychosis (DP) is a composite semi-structured standardized interview schedule. It combines social and demographic descriptors with measures of functioning adapted from the World Health Organisation Disability Assessment Schedule (DAS). The remand centre surveyed had 466 cells and is the main remand and reception centre for males for the southern region of the state of Queensland, Australia. Of the 621 men screened, 65 answered yes to at least one question in the DP and were interviewed. RESULTS: Six hundred and twenty-one remandees were screened and of these 61 were interviewed as screened positive for psychotic disorder. Thirty-five per cent had been homeless for an average of 32 weeks during the previous year. Most had had little contact with families or close friends. Eighty-one per cent were receiving no treatment at the time of offence. Seventy-eight per cent were unemployed and in receipt of a pension. Eighty per cent were dependent on alcohol, cannabis or amphetamines. Statistical issues of power are detailed in the text. CONCLUSIONS: The simplistic 'prison, hospital or community treatment' debate is misleading. Instead, the development of flexible preventative, management and accommodation services for people with severe mental disorder who have committed offences is a priority.

Adult↗
PubMed2006

Work performance among Australians with depression and anxiety disorders: a population level second order analysis.

At a population level, little is known about how anxiety and depression impact on work performance. We investigated the first and second order correlates of work accomplishment and care taken at work among people with International Statistical Classification of Diseases and Related Health Problems, 10th Revision, affective and anxiety disorders in comparison to healthy community residents. Australian Bureau of Statistics multistage sampling strategies obtained a household sample of 37,580 working age individuals. A secondary analysis was conducted using multiple binary logistic regression. The first order correlates of work performance were the extent of employment restrictions, mental health status, age, sex, and whether or not treatment was received. At the second order level, the effects of mental health status on work performance depended on age, sex, and receiving treatment. The effect of employment restrictions on work performance depended on age and sex only.

Adolescent↗
PubMed2005

Psychotic-like experiences in the general community: the correlates of CIDI psychosis screen items in an Australian sample.

BACKGROUND: Apart from individuals with clinical psychosis, community surveys have shown that many otherwise well individuals endorse items designed to identify psychosis. The aim of this study was to characterize the demographic correlates of individuals who endorse psychosis screening items in a large general community sample. METHOD: The National Survey of Mental Health and Wellbeing interviewed 10641 individuals living in private dwellings in Australia. As part of a diagnostic interview (the CIDI), respondents were asked between three and six items originally designed to screen for potential psychosis. We examined the impact of selected demographic variables on endorsement of these items including sex, age, marital status, migrant status, urban/rural status, employment, education, and socio-economic status. RESULTS: An estimated 11.7% of the Australian population endorsed at least one psychosis-screening item. Significantly higher endorsement was associated with younger age, migrants from non-English-speaking backgrounds, those who had never married or who were divorced/separated or unemployed, those living in urban regions and those from the lowest socio-economic levels. CONCLUSIONS: Many of the correlates of endorsement of psychosis-screen items are also associated with psychosis. Unravelling the factors that contribute to this broader non-clinical phenotype will aid our understanding of psychosis.

Adolescent↗
PubMed2005

A systematic review of the prevalence of schizophrenia.

BACKGROUND: Understanding the prevalence of schizophrenia has important implications for both health service planning and risk factor epidemiology. The aims of this review are to systematically identify and collate studies describing the prevalence of schizophrenia, to summarize the findings of these studies, and to explore selected factors that may influence prevalence estimates. METHODS AND FINDINGS: Studies with original data related to the prevalence of schizophrenia (published 1965-2002) were identified via searching electronic databases, reviewing citations, and writing to authors. These studies were divided into "core" studies, "migrant" studies, and studies based on "other special groups." Between- and within-study filters were applied in order to identify discrete prevalence estimates. Cumulative plots of prevalence estimates were made and the distributions described when the underlying estimates were sorted according to prevalence type (point, period, lifetime, and lifetime morbid risk). Based on combined prevalence estimates, the influence of selected key variables was examined (sex, urbanicity, migrant status, country economic index, and study quality). A total of 1,721 prevalence estimates from 188 studies were identified. These estimates were drawn from 46 countries, and were based on an estimated 154,140 potentially overlapping prevalent cases. We identified 132 core studies, 15 migrant studies, and 41 studies based on other special groups. The median values per 1,000 persons (10%-90% quantiles) for the distributions for point, period, lifetime, and lifetime morbid risk were 4.6 (1.9-10.0), 3.3 (1.3-8.2), 4.0 (1.6-12.1), and 7.2 (3.1-27.1), respectively. Based on combined prevalence estimates, we found no significant difference (a) between males and females, or (b) between urban, rural, and mixed sites. The prevalence of schizophrenia in migrants was higher compared to native-born individuals: the migrant-to-native-born ratio median (10%-90% quantile) was 1.8 (0.9-6.4). When sites were grouped by economic status, prevalence estimates from "least developed" countries were significantly lower than those from both "emerging" and "developed" sites (p = 0.04). Studies that scored higher on a quality score had significantly higher prevalence estimates (p = 0.02). CONCLUSIONS: There is a wealth of data about the prevalence of schizophrenia. These gradients, and the variability found in prevalence estimate distributions, can provide direction for future hypothesis-driven research.

Epidemiologic Studies↗
PubMed2005

The importance of modelling heterogeneity in complex disease: application to NIMH Schizophrenia Genetics Initiative data.

As for other complex diseases, linkage analyses of schizophrenia (SZ) have produced evidence for numerous chromosomal regions, with inconsistent results reported across studies. The presence of locus heterogeneity appears likely and may reduce the power of linkage analyses if homogeneity is assumed. In addition, when multiple heterogeneous datasets are pooled, inter-sample variation in the proportion of linked families (alpha) may diminish the power of the pooled sample to detect susceptibility loci, in spite of the larger sample size obtained. We compare the significance of linkage findings obtained using allele-sharing LOD scores (LOD(exp))-which assume homogeneity-and heterogeneity LOD scores (HLOD) in European American and African American NIMH SZ families. We also pool these two samples and evaluate the relative power of the LOD(exp) and two different heterogeneity statistics. One of these (HLOD-P) estimates the heterogeneity parameter alpha only in aggregate data, while the second (HLOD-S) determines alpha separately for each sample. In separate and combined data, we show consistently improved performance of HLOD scores over LOD(exp). Notably, genome-wide significant evidence for linkage is obtained at chromosome 10p in the European American sample using a recessive HLOD score. When the two samples are combined, linkage at the 10p locus also achieves genome-wide significance under HLOD-S, but not HLOD-P. Using HLOD-S, improved evidence for linkage was also obtained for a previously reported region on chromosome 15q. In linkage analyses of complex disease, power may be maximised by routinely modelling locus heterogeneity within individual datasets, even when multiple datasets are combined to form larger samples.

Chromosomes, Human, Pair 10↗
PubMed2005

Rates of treated schizophrenia and its clinical and cultural features in the population isolate of the Iban of Sarawak: a tri-diagnostic approach.

BACKGROUND: We present results of a study of treated rates of schizophrenia among the Iban of Sarawak, Malaysia. Most Iban live in longhouses, each comprising a kindred group of up to 300 individuals. Cultural practices such as minimal intermarriage with members of adjacent ethnic groups and in-depth genealogical knowledge make them a population suitable for genetic investigation. Iban culture is conducive to a focus on symptoms and illness, and to patterns of treatment-seeking behaviour that are enthusiastic and persistent. METHOD: We identified all known cases of psychotic disorder within a defined catchment area based on an exhaustive survey of available medical records. From corresponding Malaysian census data (91,056 persons), we report rates of treated schizophrenia in the Iban population, using three diagnostic systems, as well as the demographic and clinical characteristics of these individuals. RESULTS: The most frequent presenting complaints were insomnia and aggression. We found higher treated rates for narrowly defined schizophrenia among males, but no significant gender difference for age of onset. Estimates of treated rates to age 55 years (per 10,000) for narrow schizophrenia were 41.9 (ICD-10), 56.5 (DSM-IV), and 83 (RDC), while the rates for broad schizophrenia were 105.5, 103.2, and 107.5 respectively. CONCLUSIONS: Treated rates of schizophrenia were higher than the reported prevalence for many populations at risk, including many small-scale societies, although different methodological approaches may partly explain these findings. Given the cultural patterns of Iban treatment-seeking behaviour, treated rates of schizophrenia reported here may closely approximate the population prevalence of this disorder.

Adolescent↗
PubMed2005

Work-related subjective experiences among community residents with schizophrenia or schizoaffective disorder.

OBJECTIVE: To develop a self-report scale of subjective experiences of illness perceived to impact on employment functioning, as an alternative to a diagnostic perspective, for anticipating the vocational assistance needs of people with schizophrenia or schizoaffective disorders. METHOD: A repeated measures pilot study (n(1) = 26, n(2) = 21) of community residents with schizophrenia identified a set of work-related subjective experiences perceived to impact on employment functioning. Items with the best psychometric properties were applied in a 12 month longitudinal survey of urban residents with schizophrenia or schizoaffective disorder (n(1) = 104; n(2) = 94; n(3) = 94). RESULTS: Construct validity, factor structure, responsiveness, internal consistency, stability, and criterion validity investigations produced favourable results. Work-related subjective experiences provide information about the intersection of the person, the disorder, and expectations of employment functioning, which suggest new opportunities for vocational professionals to explore and discuss individual assistance needs. CONCLUSION: Further psychometric investigations of test-retest reliability, discriminant and predictive validity, and research applications in supported employment and vocational rehabilitation, are recommended. Subject to adequate psychometric properties, the new measure promises to facilitate exploring: individuals' specific subjective experiences; how each is perceived to contribute to employment restrictions; and the corresponding implications for specialized treatment, vocational interventions and workplace accommodations.

Adolescent↗
PubMed2005

Prevalence of intellectual disability and comorbid mental illness in an Australian community sample.

OBJECTIVE: The aim of this study was to bring to light the high prevalence of Australians affected by intellectual disability and comorbid serious mental illnesses. Results from a broad scale study are used to explore the reasons for this regularly overlooked phenomenon. METHODS: This study was based on secondary analysis of data collected in the national 'Disability, Ageing and Carers Survey, 1998'. The analysed data consisted of an Australian wide sample of 42 664 individuals living at home or in cared accommodation. Classification of intellectual disability and comorbid psychosis, anxiety and depressive disorder was based on the International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10). RESULTS: The prevalence of intellectual disability in the sampled population was 1.25%. Of these people 1.3% had a psychotic disorder, 8% had a depressive disorder and 14% had an anxiety disorder that had been present for at least 6 months and was of such severity that it too was disabling. CONCLUSIONS: Findings indicate that people with intellectual disability are at high risk of developing comorbid serious mental illness. Dual diagnosis is however, often overlooked due to difficulties associated with establishing a diagnosis of a mental disorder in people with an intellectual disability, a problem which is heightened when the individual's capacity to participate in a clinical assessment is limited.

Adolescent↗
PubMed2005

Work-related self-efficacy among community residents with psychiatric disabilities.

A new measure of work-related self-efficacy for people with psychiatric disabilities is reported. The 37-item scale measures self-efficacy in four relevant activity domains: (1) vocational service access and career planning, (2) job acquisition, (3) work-related social skills, and (4) general work skills. The scale was developed in a 12-month longitudinal survey of urban residents diagnosed with schizophrenia or schizoaffective disorder (n=104). Results indicate validity of both a four-factor structure differentiating four core skill domains, and a single factor representing total work-related self-efficacy. The favorable psychometric properties support further research and trial applications in supported employment and psychiatric vocational rehabilitation.

Adult↗
PubMed2004

A systematic review of the incidence of schizophrenia: the distribution of rates and the influence of sex, urbanicity, migrant status and methodology.

BACKGROUND: Understanding variations in the incidence of schizophrenia is a crucial step in unravelling the aetiology of this group of disorders. The aims of this review are to systematically identify studies related to the incidence of schizophrenia, to describe the key features of these studies, and to explore the distribution of rates derived from these studies. METHODS: Studies with original data related to the incidence of schizophrenia (published 1965-2001) were identified via searching electronic databases, reviewing citations and writing to authors. These studies were divided into core studies, migrant studies, cohort studies and studies based on Other Special Groups. Between- and within-study filters were applied in order to identify discrete rates. Cumulative plots of these rates were made and these distributions were compared when the underlying rates were sorted according to sex, urbanicity, migrant status and various methodological features. RESULTS: We identified 100 core studies, 24 migrant studies, 23 cohort studies and 14 studies based on Other Special Groups. These studies, which were drawn from 33 countries, generated a total of 1,458 rates. Based on discrete core data for persons (55 studies and 170 rates), the distribution of rates was asymmetric and had a median value (10%-90% quantile) of 15.2 (7.7-43.0) per 100,000. The distribution of rates was significantly higher in males compared to females; the male/female rate ratio median (10%-90% quantile) was 1.40 (0.9-2.4). Those studies conducted in urban versus mixed urban-rural catchment areas generated significantly higher rate distributions. The distribution of rates in migrants was significantly higher compared to native-born; the migrant/native-born rate ratio median (10%-90% quantile) was 4.6 (1.0-12.8). Apart from the finding that older studies reported higher rates, other study features were not associated with significantly different rate distributions (e.g. overall quality, methods related to case finding, diagnostic confirmation and criteria, the use of age-standardization and age range). CONCLUSIONS: There is a wealth of data available on the incidence of schizophrenia. The width and skew of the rate distribution, and the significant impact of sex, urbanicity and migrant status on these distributions, indicate substantial variations in the incidence of schizophrenia.

Cohort Studies↗
PubMed2004

Vitamin D supplementation during the first year of life and risk of schizophrenia: a Finnish birth cohort study.

OBJECTIVE: Based on clues from epidemiology and animal experiments, low vitamin D during early life has been proposed as a risk factor for schizophrenia. The aim of this study was to explore the association between the use of vitamin D supplements during the first year of life and risk of developing schizophrenia. METHOD: Subjects were drawn from the Northern Finland 1966 Birth Cohort (n=9,114). During the first year of life, data were collected about the frequency and dose of vitamin D supplementation. Our primary outcome measures were schizophrenia, psychotic disorders other than schizophrenia, and nonpsychotic disorders as diagnosed by age 31 years. Males and females were examined separately. RESULTS: In males, the use of either irregular or regular vitamin D supplements was associated with a reduced risk of schizophrenia (Risk ratio (RR)=0.08, 95% CI 0.01-0.95; RR=0.12, 95% CI 0.02-0.90, respectively) compared with no supplementation. In males, the use of at least 2000 IU of vitamin D was associated with a reduced risk of schizophrenia (RR=0.23, 95% CI 0.06-0.95) compared to those on lower doses. There were no significant associations between either the frequency or dose of vitamin D supplements and (a) schizophrenia in females, nor with (b) nonpsychotic disorder or psychotic disorders other than schizophrenia in either males or females. CONCLUSION: Vitamin D supplementation during the first year of life is associated with a reduced risk of schizophrenia in males. Preventing hypovitaminosis D during early life may reduce the incidence of schizophrenia.

Adult↗
PubMed2004

Paternal and maternal age as risk factors for psychosis: findings from Denmark, Sweden and Australia.

BACKGROUND: While the association between increased maternal age and congenital disorders has long been recognized, the offspring of older fathers are also at increased risk of congenital disorders related to DNA errors during spermatogenesis. Recent studies have drawn attention to an association between increased paternal age and increased risk of schizophrenia. The aim of the current study was to examine both paternal and maternal age as risk factors for the broader category of psychosis. METHOD: We used data from three sources examining psychosis: a population-based cohort study (Denmark), and two case-control studies (Sweden and Australia). RESULTS: When controlling for the effect of maternal age, increased paternal age was significantly associated with increased risk of psychosis in the Danish and Swedish studies. The Australian study found no association between adjusted paternal age and risk of psychosis. When controlling for the effect of paternal age, younger maternal age was associated with an increased risk of psychoses in the Danish study alone. CONCLUSIONS: The offspring of older fathers are at increased risk of developing psychosis. The role of paternally derived mutations and/or psychosocial factors associated with older paternal age warrants further research.

Adolescent↗
PubMed2004

Correlates of victimisation amongst people with psychosis.

BACKGROUND: While much attention has been given to the prediction of violent offending behaviour amongst people with psychotic disorders, less attention has been given to the fact that these same individuals are often the victims of violence. In this paper, we examine victimisation amongst participants in a prevalence study of psychosis, and describe demographic and clinical correlates of victimisation. METHOD The study was based on the Australian National Survey of Mental Health and Wellbeing--Low Prevalence (Psychotic) Disorders. The participants were asked if they had been a victim of violence in the previous year. The association between selected demographic and clinical variables and being a victim of violence was examined using logistic regression. RESULTS: Of the 962 individuals with psychosis, 172 reported being a victim of violence in the past 12 months (17.9 %). The odds of being a victim were increased in those who: (a) were female, (b) were homeless, (c) had a lifetime history of substance abuse, (d) had been arrested in the previous 12 months, (e) had poorer social and occupational function, and (f) had higher scores on the disorganisation summary score. CONCLUSIONS: Clinicians should remain mindful that one out of every six individuals with a psychotic disorder reports being a victim of violence in the previous year. Models of care that address issues related to symptom relief, accommodation, and exposure to high-crime areas may reduce the rates of victimisation amongst those with psychotic disorders.

Adult↗
PubMed2004

Australian norms for a quantitative olfactory function test.

Quantitative olfactory assessment is often neglected in clinical practice, although olfactory loss can assist diagnosis and leads to significant morbidity. The aim of this study was to develop normative data for the Australian population for the 'Sniffin' Sticks', an internationally established olfactory function test. As in other populations, Australian females performed better than males and both lost olfactory function with age. From the normative data, criterion test scores for males and females were established for clinical classifications ('normosmic', 'hyposmic', and 'nosmic'). These clinical classifications were assessed in Parkinson's patients: 81.1% were anosmic or severely hyposmic and only 7.7% were normosmic. A new term ('rebyosmia') is introduced to describe age-related loss of olfactory capacity of unknown aetiology. With these norms, the Sniffin' Sticks can be used in the Australian population to compare an individual's olfactory function against the population of others of similar age and sex and to identify olfactory dysfunction.

Adolescent↗