A. E. Korten

The prevalence of dementia: A quantitative integration of the literature

ABSTRACT— Data from studies of dementia prevalence between 1945 to 1985 were analyzed statistically. Prevalence rates were found to vary as a function of methodological differences between studies. However, despite these differences, the relationship between prevalence and age was found to be consistent across studies, with rates doubling every 5.1 years. Across studies, Alzheimers disease (AD) was found to be more common in women, with a tendency for multi‐infarct dementia (MID) to be more common in men. There were also national differences in the relative prevalence of AD and MID, with MID being more commmon in Japanese and Russian studies, no difference in Finnish and American studies, and an excess of AD in other Western European countries.

A case‐control study of Alzheimer's disease in Australia

We conducted a case-control study of clinically diagnosed Alzheimers disease (AD) on 170 cases aged 52 to 96 years, and 170 controls matched for age, sex and, where possible, the general practice of origin. Trained lay interviewers naive to the hypotheses and to the clinical status of the elderly person carried out risk-factor interviews with informants. Significant odds ratios were found for 4 variables: a history of either dementia, probable AD, or Downs syndrome in a 1st-degree relative, and underactivity as a behavioral trait in both the recent and more distant past. Previously reported or suggested associations not confirmed by this study include head injury, starvation, thyroid disease, analgesic abuse, antacid use (aluminum exposure), alcohol abuse, smoking, and being left-handed.

A short form of the Positive and Negative Affect Schedule : evaluation of factorial validity and invariance across demographic variables in a community sample

Abstract The existence of two nearly-orthogonal dimensions of positive and negative affect was established for a ten-item short form of the Positive and Negative Affect Schedule using confirmatory factor analytic techniques in a large probability sample (n=2651) spanning ages 18 to 79. The factor structure and factor correlations were found to be unchanged with age. A multiple indicators, multiple causes model was used to investigate differences in item responses according to age, sex, education, marital status and financial hardship that could not be accounted for by differences in affect levels between groups. Only one item, excited from the Positive Affect scale, was found to elicit differential responses. While improvements to the Positive Affect scale might be desirable, the Short PANAS can be recommended for use when measures of positive and negative affect are required.

Using the BIS/BAS scales to measure behavioural inhibition and behavioural activation : Factor structure, validity and norms in a large community sample

Abstract The Behavioural Inhibition System and Behavioural Activation System (BIS/BAS) scales of Carver and White (1994) were used in an Australian community sample of 2725 individuals aged 18–79. Factor analysis of the BIS/BAS items supported the 4-factor structure found by Carver and White, as well as a 2-factor structure reflecting separate behavioural inhibition and behavioural activation systems. The BIS scale was related to neuroticism and negative affectivity, while the BAS scale was related to extraversion and positive affectivity. The BIS scale was less correlated with anxiety and depression symptoms than are neuroticism and negative affectivity scales, probably because it is designed to measure predisposition to anxiety rather than the experience of anxiety. BIS scores were higher in females, while the BAS subscales showed a more complex pattern, with reward responsiveness scores higher in females and drive scores higher in males. Both BIS and BAS scores were lower in older age groups, suggesting the possibility that the behavioural inhibition and behavioural activation systems become less responsive with age.

Psychotic disorders in urban areas: an overview of the study on low prevalence disorders

Objective: This paper reports on a study designed within the framework of the National Survey of Mental Health and Wellbeing to: estimate the prevalence of psychoses in urban areas of Australia; identify profiles of symptomatology, impairments and disabilities; collect information on services received and needed; and explore quality of life issues in a broadly representative sample of people with psychotic illnesses. Method: The study was conducted over four areas in the Australian Capital Territory, Queensland, Victoria and Western Australia, as a two-phase survey: (i) a census and screening for psychosis of all individuals who made contacts with mental health services during a period of 1 month in 1997; and (ii) interviews with a stratified random sample (n = 980) of the screen-positive individuals (n = 3800) using a standardised instrument. Results: The point prevalence (1 month) of psychotic disorders in the urban population aged 18–64 is in the range of 4–7 per 1000 with a weighted mean of 4.7 per 1000. People with psychotic disorders experience high rates of functional impairments and disability, decreased quality of life, persistent symptoms, substance-use comorbidity and frequent side effects of medication. Although the utilisation of hospital-based and community mental health services, as well as of public and non-governmental helping agencies, is high, the majority live in extreme social isolation and adverse socioeconomic circumstances. Among the many unmet needs, the limited availability of community-based rehabilitation, supported accommodation and employment opportunities is particularly prominent. Conclusions: The so-called ‘low-prevalence’ psychotic disorders represent a major and complex public health problem, associated with heavy personal and social costs. There is a need for a broad programmatic approach, involving various sectors of the community, to tackle the multiple dimensions of clinical disorder, personal functioning and socioeconomic environment that influence the course and outcome of psychosis and ultimately determine the effectiveness of service-based intervention.

Attitudes towards people with a mental disorder: a survey of the Australian public and health professionals

Objective: The aim of this paper was to compare the Australian publics attitudes towards people who have been treated for a mental disorder with the attitudes of general practitioners, psychiatrists and clinical psychologists. Method: The study involved a household survey of 2031 members of the Australian public and a postal survey of 872 general practitioners, 1128 psychiatrists and 454 clinical psychologists. Survey participants were presented with a vignette describing a person with schizophrenia or one with depression. They were asked opinions about the persons long-term outcome in various areas of life after receiving treatment. Participants were also asked whether they thought the person described would be discriminated against by others. Results: Both the public and professionals rated outcomes as poorer and discrimination as more likely for the person with schizophrenia than for the one with depression. The professionals made more negative ratings than the public, although the clinical psychologists had similar attitudes to the public about depression. Conclusions: Compared to the public, health professionals rate long-term outcomes more negatively and discrimination as more likely. It is possible that these more negative attitudes are realistic, being based on greater knowledge of mental disorders. However, professional attitudes may be biased by greater contact with patients who have chronic or recurrent disorders. Either way, health professionals need to be aware of the effects that their negative attitudes might have on patients and the public.

Apolipoprotein E allele ∈4, dementia, and cognitive decline in a population sample

From clinically based series it has been proposed that, in homozygotes for the apolipoprotein E epsilon 4 (apoE epsilon 4) allele, Alzheimers disease is almost inevitable by the age of 80. A population sample of persons aged 70 years and over was interviewed in 1990-91 to ascertain the presence of dementia or cognitive impairment. The sample was reinterviewed in 1994, when the apoE genotype was also determined. Prevalence data for the 638 persons who completed the second examination revealed a linear association between having an apoE epsilon 4 allele and both dementia and cognitive impairment (for heterozygotes, odds ratio for dementia 1.89, 95% confidence interval 1.04-3.44 and for homozygotes OR 3.58, 95% CI 1.08-11.82; both adjusted for age). However, even in subjects homozygous for epsilon 4 the estimated prevalence of dementia by age 90 was only about 50%. Persons with one or two epsilon 4 alleles were more likely to have a family history of dementia than those with none. This study confirms in a population sample that the epsilon 4 allele is a risk factor for dementia, but refutes the suggestion that homozygosity for the epsilon 4 allele is sufficient for the development of Alzheimers disease: persons with either one or two epsilon 4 alleles may reach late old age without cognitive impairment.

The course of depression in the elderly : a longitudinal community-based study in Australia

BACKGROUND We report the outcome of depressive states after 3-4 years in a community sample of the elderly. METHODS A sample of 1045 persons aged 70+ years in 1990-1 was re-interviewed after 3.6 years. RESULTS Mortality (21.7%) and refusal or non-availability (10.4%) were higher in those who initially had had a diagnosis or symptoms of depression. Of those with an ICD-10 depressive episode in 1990-1, 13% retained that diagnosis. Of those who were not depressed initially only 2.5% had become cases. Depression was unrelated to age or apolipoprotein E genotype. The best predictors of the number of depressive symptoms at follow-up was the number at Wave 1, followed by deterioration in health and in activities of daily living, high neuroticism, poor current health, poor social support, low current activity levels and high service use. Depressive symptoms at Wave 1 did not predict subsequent cognitive decline or dementia. CONCLUSIONS Non-random sample attrition is unavoidable. ICD-10 criteria yield more cases than other systems, while continuous measures of symptoms confer analytical advantages. Risk factors for depressive states in the elderly have been further identified. The prognosis for these states is favourable. At the community level, depressive symptoms do not seem to predict cognitive decline, as they do in referred series.

Do cognitive complaints either predict future cognitive decline or reflect past cognitive decline? A longitudinal study of an elderly community sample

Data from a two-wave longitudinal study of an elderly community sample were used to assess whether cognitive complaints either predict subsequent cognitive decline or reflect past cognitive decline. Cognitive complaints and cognitive functioning were assessed on two occasions three and a half years apart. Cognitive complaints at Wave 1 were found not to predict future cognitive change on the Mini-Mental State Examination, an episodic memory test or a test of mental speed. Similarly, cognitive complaints at Wave 2 were unrelated to past cognitive changes on these tests after statistically controlling for the effects of anxiety and depression. Furthermore, cognitive complaints did not predict either mortality (after controlling for anxiety and depression) or future dementia. These results are evidence against the inclusion of cognitive complaints in diagnostic criteria for proposed disorders such as age-associated memory impairment, mild cognitive disorder and ageing-associated cognitive decline.

Public beliefs about causes and risk factors for depression and schizophrenia.

The objective of this study was to carry out a national survey to assess the Australian publics beliefs about causes and risk factors for mental disorders. A national household survey of 2,031 Australian adults was carried out. Half the respondents were presented with a vignette describing a person with major depression and the other half with a vignette describing schizophrenia. Respondents were asked to rate whether various factors are likely causes of problems such as that described in the vignette and to rate whether various groups are at higher or lower risk. For depression, social environmental factors were often seen as likely causes, which is consistent with the epidemiological evidence. However, genetic factors were considered as a likely cause by only half the population. For schizophrenia, social environmental factors were also often seen as causes, which is in contrast to the weak epidemiological evidence for such a role. Genetic factors attracted more support as a cause of schizophrenia than of depression. These finding point to areas where the mental health literacy of the population could be improved, particularly the over-emphasis on social environmental factors in schizophrenia. Of some concern was the belief of half the population that weakness of character is a likely cause of both depression and schizophrenia. This belief implies a negative evaluation of the sufferer as a person.