Biomedical subjects

A J Mackinnon

Publications and source records attributed to A J Mackinnon.

41 records · Page 3Linked to original sources

PubMed1990

Genetic and environmental determinants of the lability of trait neuroticism and the symptoms of anxiety and depression.

A genetic analysis was conducted on trait neuroticism and symptoms of anxiety and depression in a five-wave study of 462 twin pairs. Models that assessed the relative importance of genetic and environmental factors to the lability (within-individual variability over time) of these measures were fitted to the data. Previous results concerning the substantial genetic involvement in the level of neuroticism and symptoms were confirmed. However, it was found that neither genes nor the shared environment of the twins was a significant cause of lability of these measures. An attempt was therefore made to identify aspects of individuals' environments that might be responsible for lability of neuroticism and symptoms. Adverse life events were found to predict variability of symptoms, but not of neuroticism. The availability of close social ties or having affectionless control in childhood did not contribute to lability.

Adult↗

PubMed1989

The Parental Bonding Instrument (PBI): an epidemiological study in a general population sample.

The Parental Bonding Instrument (PBI) was used in a 2-wave community survey of 386 persons. The two factor structure of the instrument was confirmed, as well as the high stability of its scales over time. Respondents who had had children differed significantly from others. No association was found between social desirability, neuroticism or extraversion and either of the scales. No association was observed between the scales and psychiatric disorder, despite using covariance structure analysis to remove the effects of age and attenuation due to measurement error. Estimates of relative risk for affectionless control were low in contrast to estimates calculated from samples with psychiatric disorders. These findings may be characteristic of symptomatic persons in a general population. Because of the importance of the affectionless control construct, the findings invite further investigation in other community and treated samples.

Adolescent↗

PubMedDate not supplied

Comparing correlated kappas by resampling: is one level of agreement significantly different from another?

Researchers comparing diagnostic systems or screening tests frequently need to compare indices of agreement such as the kappa coefficient. While asymptotic methods exist for comparing kappas derived from independent samples, no satisfactory approach exists for comparing kappas derived from the same or related samples. Resampling methods for comparing kappa coefficients obtained from the same sample are presented. Easily undertaken using readily available software, these methods are illustrated by application to a small sample of psychiatric data, as well as to several thousand samples of simulated data. An acceptable type I error rate was exhibited. Resampling techniques-easily implemented and making few assumptions-deserve wider application in psychiatric research.

Adult↗

PubMedDate not supplied

Are changes in sensory disability, reaction time, and grip strength associated with changes in memory and crystallized Intelligence? A longitudinal analysis in an elderly community sample.

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.

Aged↗

PubMedDate not supplied

Dimensions of psychopathology in the medically ill. A latent trait analysis.

The authors examined the latent structure of psychiatric symptoms occurring in patients with medical illness. Symptom data were collected from 312 hospitalized medically ill patients using the Monash Interview for Liaison Psychiatry and subjected to latent trait analysis. A model with 5 dimensions provided an acceptable fit to the data. Dimensions were characterized as demoralization, anhedonia, autonomic anxiety, somatic symptoms, and grief. The demoralization dimension was similar to the concept of demoralization described by Frank and to the "giving up-given up complex" described by Engel. The concepts of demoralization, grief, and anhedonia may be useful in increasing understanding of the minor depressions in people with medical illness and in increasing the specificity of psychological and pharmacological treatments for these disorders.

Adaptation, Psychological↗