Biomedical subjects

P Jacomb

Publications and source records attributed to P Jacomb.

5 recordsLinked to original sources

PubMed1999

An analysis of diversity in the cognitive performance of elderly community dwellers: individual differences in change scores as a function of age.

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.

Activities of Daily Living↗

PubMed1998

Symptoms of depression and anxiety during adult life: evidence for a decline in prevalence with age.

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.

Adolescent↗

PubMed1997

A prospective study of cognitive function in the elderly.

BACKGROUND: We report on the change in cognitive function in a population sample of elderly people who have been examined on two occasions more than 3 years apart. METHODS: A sample of 1135 persons aged 70-102 years was interviewed at base-line then re-interviewed 3.6 years later with the Canberra Interview for the Elderly, which included tests of episodic memory and cognitive speed as well as the Mini-Mental State Examination and the National Adult Reading Test (NART). RESULTS: Mortality and loss to follow-up reduced the sample to 736, of whom 614 completed at least one test of cognitive performance on both occasions. Cognitive performance decreased with age, except on the NART. Decline over the follow-up period increased as a function of age in all cognitive measures, except the NART. Change in cognitive scores was close to normal distribution. Incident dementia was associated strongly with age and current level of cognitive performance, but not with rate of decline. Cognitive decline and the risk of incident dementia did not differ by gender. CONCLUSIONS: A score indicating possible impairment in the very elderly carries a worse prognosis than for the younger elderly. Decline is almost universal in at least one cognitive area among those over the age of 85.

Aged↗

PubMed1997

A quantitative review of cognitive deficits in depression and Alzheimer-type dementia.

Meta-analysis was used to examine the performance of depressed and Alzheimer-type dementia (DAT) patients on standard and experimental clinical tests of cognitive function. Deficits were found for depression on almost every psychological test. Relative to nondepressed controls, the average deficit was 0.63 of a standard deviation, but the magnitude of the effect varied with the type of test. DAT patients performed worse than depressed patients, with an average effect size of 1.21 standard deviations, but the size of the effect depended on the clinical test. Effect sizes for the comparison between depressives and controls were significantly affected by age, treatment setting, ECT use, severity of depression, and the source of diagnostic criteria, but not by the type of depression. Effect sizes in the comparison of depressives to DAT patients were influenced by age, the severity of depression, and ECT. Depressives performed proportionately worse than controls on tasks with pleasant or neutral, compared with unpleasant content, on speeded compared with nonspeeded tasks, and on vigilance tasks. However, there were no differences in the magnitude of effect size for tests using recall compared with recognition, using categorical compared with noncategorical word lists, on story compared with word comprehension, and using verbal compared with visual material. Relative to DAT patients, depressives performed no better on recall compared to recognition tasks, or verbal compared to visual material. The findings of the review are not consistent with the hypothesis that depression is associated with deficits in effortful processing. A model of psychological deficit in depression as a deficit in speed or attention has more promise.

Aged↗

PubMedDate not supplied

Molecular genetics and the epidemiology of common mental disorders: new opportunities.

AIM: To describe the rationale for introducing molecular genetic analyses to psychiatric epidemiology. This offers new possibilities for aetiological research on common mental disorders. METHODS: In addition to the traditional variables used in field surveys, it is now possible to include molecular genetic information. This is currently done by looking for allelic associations rather than by linkage analysis, and can be directed either at traits conferring susceptibility or at states. The purpose is to identify quantitative trait loci (QTLs) by examining candidate genes. An alternative strategy is genome scanning, which can identify genes by their chromosomal position with increasing resolution. RESULTS: Some associations have already been reported in the literature, linking personality traits with particular alleles extraversion or novelty-seeking with a polymorphism of the dopamine DRD4 receptor gene; and neuroticism with a polymorphism of the serotonin transporter gene. CONCLUSIONS: These findings are of major interest, but cannot yet be looked upon as confirmed. What is significant for epidemiology is the opportunity to link behavioural and psychiatric variables with genes influencing biochemical and physiological processes in the brain, and to do so at the population level. For further allelic association studies, there are four principal requirements: valid measures of phenotypes; replication of findings across diverse populations; more candidate genes; and exploration of the interaction between genotype and environmental exposures from conception to late life. Through such research, psychiatric epidemiology can now investigate biopsychosocial phenomena.

Humans↗