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AIMS: It is timely to ask what epidemiology has brought to our knowledge about mental illness and what information is proving of particular value. In this task, the first step is to identify the truly fundamental questions that the epidemiology of mental disorders should be expected to answer. This review is selectively directed at four such questions. METHODS: A small number of significant publications were identified. RESULTS: The extent to which some major questions in epidemiology have been answered is examined. CONCLUSIONS: When considered alongside epidemiological knowledge elsewhere in medicine, psychiatric epidemiology has indisputably proved to be a powerful tool. Descriptive studies have been particularly useful for advocacy and policy, while analytic studies of aetiology have yielded some valuable clues. There are now signs that linkage with neuroscience will bring further progress in understanding the causes of mental disorders.

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OBJECTIVE: Examinations are anecdotally viewed as extremely stressful to Singapore schoolchildren. We test this postulate by obtaining parental ratings of children's emotional stress levels longitudinally in a large representative sample of sixth (P6) and fifth (P5) class primary schoolchildren, respectively, exposed and unexposed to a streaming examination. METHOD: Children's stress levels were rated monthly by a parent for 10 months. RESULTS: Analyses failed to find evidence of any differential stress impact across P6 and P5 comparison groups, apart from a subset of P6 children whose parents complied with every monthly survey. CONCLUSION: The streaming examination in the final year of primary school did not emerge as a general stressor to children, but achieved salience within a defined subset of children whose parents were highly study compliant. Study compliance may be a proxy variable of some import, and have wider relevance to other cohort studies and to intervention trials.

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BACKGROUND: There is considerable dispute about the validity of memory complaints. While some studies find that complaints are an early indicator of dementia or cognitive decline, there are also many studies showing that complaints are more closely associated with negative affect (depression, anxiety and neuroticism). The present paper used three-wave longitudinal data to test three hypotheses: (1) that memory complaints reflect an evaluation of present and past memory performance; (2) that memory complaints predict future memory performance; and (3) that memory complaints predict current and future negative affect. METHODS: A longitudinal study was carried out with a community sample of people aged 70 and over. Participants were assessed for memory complaints, memory performance and negative affect at three waves separated by 3.6 years and 4.0 years. There were 331 persons with data on all relevant variables. The data were analysed using structural equation modelling. RESULTS: Significant paths in the structural model were found from memory performance to future memory complaints, as well as from memory complaints to future memory performance, supporting hypotheses 1 and 2. Memory complaints were associated with current negative affect, but did not predict future negative affect. CONCLUSIONS: Memory complaints do reflect perceptions of past memory performance and are also an early manifestation of memory impairment. However, current negative affect (anxiety and depression symptoms) shows the greatest association with memory complaints.

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BACKGROUND: Higher education has been posited to protect against cognitive decline, either because the rate of decline is slower in the more highly educated or the start of decline is delayed. Latent growth models provide improved methodology to examine this issue. METHODS: The sample consisted of 887 participants aged 70-93 years in 1991 and followed up in 1994 and 1998. Latent growth models and standard regression techniques were used to examine the rate of cognitive decline in four cognitive measures while controlling for health status and sex. A delayed start model was examined by incorporating interaction effects in a regression model. RESULTS: Neither the latent growth models nor the regression techniques revealed a slower rate of decline for the more highly educated. The proportion of the highly educated showing no change was no larger than the proportion of the less well educated. There were no significant age by education interaction effects, no chronologically later accelerations in the rate of change as a function of education, and no differences in rate of decline between the first measurement interval and the second. CONCLUSIONS: Education may not protect against cognitive decline although it is associated with long-term individual differences in level of functioning. The discrepancy between our study and others may be attributable to attrition effects, follow-up length, sample age, scaling artefacts and negative publication bias. Most importantly, practice effects may favour the better educated and hence account for the supposed protective effect in many longitudinal studies of cognitive change.

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BACKGROUND: Informant questionnaires on cognitive decline are increasingly used as screening tests for dementia. Informants can provide a longitudinal perspective that is not possible with cognitive screening tests administered at one point in time. However, there are limited data on the validity of such questionnaires when judged against longitudinal change on cognitive tests. METHODS: A community sample of elderly people aged > or = 70 was assessed on cognitive tests at baseline and after a follow-up of 7-8 years. The participants were given the Mini-Mental State Examination and tests of episodic memory and mental speed. At follow-up, the short-form of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) was completed by informants for 287 of the participants. RESULTS: Elderly people who were rated by informants as having moderate or severe decline had declined significantly on cognitive tests. The IQCODE correlated as highly with cognitive test change scores as these change scores correlated with each other. CONCLUSIONS: The IQCODE is a valid way of assessing cognitive decline when assessment can be carried out only at one point in time.

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A functional polymorphism in the promoter of the monoamine oxidase gene has recently been described by Sabol et al. This polymorphism is a strong candidate for associations with personality traits and psychiatric symptoms. We report relevant data from a general population sample of 850 Caucasian Australians. We found no associations with anxiety and depression symptoms, with personality traits that predispose to anxiety (neuroticism, behavioral inhibition, negative affect) or to a personality trait related to antisocial behavior (psychoticism).

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BACKGROUND: Little is known about predictors of cognitive changes in the elderly. Sensory disability, grip strength, and speed of processing have been established as associates of cognitive performance in cross-sectional studies. However, it is not known whether changes in these predictor variables are associated with changes in cognitive functioning. OBJECTIVES: (1) to examine the relationship between initial level of three predictor variables - speed of processing, sensory disability, and grip strength - and changes in memory and crystallized intelligence (CIQ); (2) to examine the relationships between change in grip strength, cognitive speed, and sensory disability and changes in memory and CIQ, and (3) to investigate these relationships with the effects of age and sex statistically removed. METHODS: Cognitive ability was assessed in two domains: CIQ (3 tests) and memory (3 tests) measured on two occasions approximately three and a half years apart in a large community sample (n = 425; mean age = 75.8, range 70-93 years). Repeated-measures Anova was used to analyze descriptive data. Latent-change models were used to examine structural relationships between constructs. RESULTS: Initial levels of reaction time or grip strength did not predict rate of change on memory tasks. Changes in grip strength, speed, and memory correlated moderately, suggesting that these variables have some tendency to move together over time. Sensory disability correlated with age but not with change in speed, grip, memory, or CIQ. These relationships held across the age range studied after adjustment for age and sex. CONCLUSIONS: The findings are consistent with the action of a common causal mechanism underlying changes in speed, grip, and memory. A number of methodological caveats arise from our analysis. Cross-sectional and longitudinal data sets yield different interpretations about the basic component associates of cognitive performance.

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In studies that used mixed volunteer samples, Lerman et al. [1999: Health Psychol 18:14-20] and Sabol et al. [1999: Health Psychol 18:7-13] reported on an association of smoking with a polymorphism of the dopamine transporter gene. We attempted to replicate this association in a nonvolunteer community sample of 861 Caucasians. No associations were found with either smoking initiation or smoking cessation. Sabol et al. [1999] also reported on an association of the dopamine transporter polymorphism with the personality trait of novelty seeking. However, we failed to find any associations with a range of personality traits, including a scale of fun seeking that correlates with novelty seeking. These negative findings suggest that either the original associations are not replicable or that any association is very small.

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BACKGROUND: Many studies have demonstrated co-morbidity of alcohol abuse/dependence with mood and anxiety disorders but relatively little is known about anxiety and depression across the full continua of alcohol consumption and problems associated with drinking. METHODS: Participants from a general population sample (N = 2725) aged 18-80 years completed the Alcohol Use Disorders Identification Test (AUDIT) and four measures of negative affect (two depression and two anxiety symptom scales) included in a self-completion questionnaire. RESULTS: High consumption, AUDIT total score, and AUDIT problems score were associated with high negative affect scores in participants under 60 years old (ORs in the range 1.80-2.83). Graphical and statistical analyses using continuous measures of alcohol use/problems and negative affect identified non-linear relationships where abstainers and occasional drinkers, as well as heavy and problem drinkers, were at risk of high anxiety and depression levels. This pattern, however, was not found in those aged > or = 60 years. The U-shaped relationship was not an artefact of abstainers being typical of the general population in their distribution of negative affect. CONCLUSIONS: Studies of co-morbidity should acknowledge the possibility of non-linear associations and employ both continuous and discrete measures. Abstainers, as well as heavy drinkers, are at increased risk of symptoms of depression and anxiety disorders. Psychosocial factors may play a role in the U-shaped relationship between alcohol consumption and mortality.

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In a longitudinal study of college students, B. S. Gershuny and K. J. Sher (1998) found that high neuroticism and low extraversion had a synergistic effect in predicting anxiety and depression 3 years later. This article attempted to replicate their finding using data from 2 community samples: (a) a cross-sectional survey of 2,677 persons aged 18-79 years, and (b) a longitudinal study in which 441 persons aged 70 or older were followed over 3-4 years. Both studies found that neuroticism predicted anxiety and depression, but there were no Neuroticism x Extraversion interaction effects. These results cast doubt on the generalizability of the original findings.

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In a community sample of 2,327 Caucasians, we tested the hypotheses that polymorphisms in the COMT and DRD3 genes are associated with personality traits conferring vulnerability to anxiety, depression, or alcohol misuse, or with current symptoms of these; and that the association is stronger in persons who also have been exposed to stressor experiences. To conserve resources and to allow replication, the genetic analysis was undertaken in two stages. For the COMT polymorphism, no statistically significant associations were found in the first sample of 862 persons. The remainder of the sample was therefore not analysed for that gene. For the DRD3 polymorphism, those in the first sample with at least one of the Ser(9) alleles had significantly higher scores in neuroticism (p=0.006) and behavioral inhibition (p=0.003). There was a trend, failing to meet the 1% significance criterion, for those with this genotype also to have higher depression and anxiety. The groups did not differ in alcohol use. In persons with the Ser(9) allele who were also exposed to stressors, there was a higher level of depression at the 5% level; and the depression level was higher in homozygotes. But when the remainder of the sample (1,465) was analysed, none of the associations reached statistical significance. We conclude that neither the COMT nor DRD3 polymorphisms are associated with anxiety, depression, or alcohol abuse. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:102-107, 2000

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This longitudinal study investigated whether age is associated with increases in interindividual variability across 4 ability domains using a sample of 426 elderly community dwellers followed over 3.5 years. Interindividual variability in change scores increased with age for memory, spatial functioning, and speed but not for crystallized intelligence for the full sample and in a subsample that excluded dementia or probable dementia cases. Hierarchical regression analyses indicated that being female, having weaker muscle strength, and having greater symptoms of illness and greater depression were associated with overall greater variability in cognitive scores. Having a higher level of education was associated with reduced variability. These findings are consistent with the view that there is a greater range of responses at older ages, that certain domains of intelligence are less susceptible to variation than others and that variables other than age affect cognitive performance in later life.

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STUDY OBJECTIVE: To examine whether cognitive and psychosocial factors predict mortality once physical health is controlled. DESIGN: A prospective study of community dwelling elderly. Mortality was assessed over a period of 3-4 years after the baseline assessment of predictors. The data were analysed using the Cox proportional hazards model. SETTING: Canberra and Queanbeyan, Australia. PARTICIPANTS: A sample of 897 people aged 70 or over and living in the community, drawn from the compulsory electoral roll. RESULTS: For the sample as a whole, the significant predictors of mortality were male sex, poor physical health, poor cognitive functioning, and low neuroticism. Men had an adjusted relative risk of mortality of 2.5 compared with women. For the male sub-sample, poor self rated health and a poor performance on a speeded cognitive task were significant predictors, while for women, greater disability, low systolic blood pressure, and a low score on a dementia screening test were the strongest predictors. CONCLUSIONS: Mortality was predicted by physical ill health and poor cognitive functioning. Psychosocial factors such as socioeconomic status, psychiatric symptoms, and social support did not add to the prediction of mortality, once sex, physical health, and cognitive functioning were controlled. Mortality among men was more than twice that of women, even when adjusted for other predictors.

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BACKGROUND: There is debate as to whether the elderly are really at lower risk for depressive disorders, or whether endorsement of symptoms is artefactually low. The present paper assesses the effects of age on anxiety and depression, and examines whether age has direct effects on self-report of individual symptoms independent of its effect on the underlying dimensions of anxiety and depression. METHODS: Structural equation modelling was used to assess the structure of the items and their associations with age and a number of demographic variables. The sample of 2622 participants aged between 18 and 79 years from Canberra (Australia) was drawn from the Electoral Roll. Two instruments were used: the anxiety and depression scales of Goldberg et al. (1988) and the Personal Disturbance Scale from the DSSI of Bedford et al. (1976). RESULTS: Both scales were found to fit satisfactorily to a two factor model. Age correlated negatively with depression. After controlling for the effects of gender, marital status, education and financial difficulty, direct effects of age were found on items from both instruments, indicating that certain depression items were associated with a differential probability of endorsement in older people, even when the level of depression was equal to that of younger people. Items with direct age effects reflected physical (feeling slowed down; waking early) and psychological (hopeless about the future) components of depression. Direct effects of age on items from both anxiety scales were also found. CONCLUSIONS: The nature of the depression and anxiety experienced by younger and older people may differ qualitatively. Depression may be associated with an increase in somatic symptoms linked to physical changes and to an increase in endorsement of items which reflect the narrowing of opportunities in the long-term.

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Following participation in a mental health survey of 2725 adults aged 18-79, respondents were asked if the questionnaire had made them feel distressed or depressed, and if it had been an intrusion on privacy or had made them feel good about themselves. While 5% reported feeling distressed, 3% depressed and 3% were concerned about privacy, 35% reported feeling good about themselves. The participants reporting negative feelings were more likely to be younger women, to be higher on negative personality measures, to report more anxiety and depression symptoms, and to have had more childhood adversity and lower social support. Those who reported positive feelings had higher positive personality scores, more social support and lower anxiety and depression. This group was more likely to be older women. Despite the sensitive nature of many of the questions, only a small percentage of respondents reported distress, while many found that the questionnaire had made them feel good about themselves. This is important information to present to Institutional Ethics Committees and to future participants in such studies.

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BACKGROUND: To test the hypothesis that the prevalence, in the general population, of symptoms of depression and anxiety declines with age. METHODS: A general population sample of 2725 persons aged 18 to 79 years was administered two inventories for current symptoms of depression and anxiety, together with measures of neuroticism and of exposures that may confer increased risk of such symptoms. RESULTS: Symptoms of depression showed a decline with age in both men and women. For anxiety, the decline was statistically significant for women but not consistently so for men. For the risk factors examined, there was a decline with age in the neuroticism score, the frequency of adverse life events, being seriously short of money and having had parents who separated or divorced. Further analysis showed that the association between age and a declining symptom score cannot be entirely attributed to these risk factors, with the single exception of neuroticism. The latter is itself likely to be contaminated by current symptoms. CONCLUSION: Unless these findings are due to bias in the sample of those who agreed to participate, they add to the evidence that symptoms of depression and to a lesser extent of anxiety decline in prevalence with age. Some risk factors also decline with age. It now has to be determined if these cross-sectional observations are also to be found in longitudinal data; and what process may underlie this striking change in mental health during adulthood.

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A functional polymorphism in the regulatory region of the serotonin transporter gene has been reported to be associated with anxiety-related personality traits. We attempted to replicate this finding in an association study involving 759 Caucasians selected from the general Australian population. We found no associations with personality traits (including neuroticism, negative affect and behavioral inhibition), anxiety and depressive symptoms, or alcohol misuse.

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BACKGROUND: Elderly people with paranoid symptoms are a taxing group for medical and social services, but studies of the prevalence of these symptoms in the general elderly population are rare. This study aimed to estimate the community prevalence and to identify some associated variables. METHOD: A community samples of 1420 elderly people, was extensively examined by nurses and physicians. RESULTS: Paranoid ideation was found in 6.3% of the sample. The prevalence in people with cognitive dysfunction (n = 381, 12.1%) was higher than in those without (n = 1039, 2.6%). Once cognitive impairment had been controlled the associated variables were: being divorced, being female, having depressive symptoms, using psychotropic drugs, having no friends or visitors, using community care and being an immigrant. CONCLUSION: Paranoid symptoms in this elderly population were associated most strongly with cognitive impairment. Other associated variables pointed to a higher level of social isolation than others in the community.

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