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I J Deary

Publications and source records attributed to I J Deary.

18 recordsLinked to original sources
PubMed2014

Genetics and intelligence differences: five special findings.

Intelligence is a core construct in differential psychology and behavioural genetics, and should be so in cognitive neuroscience. It is one of the best predictors of important life outcomes such as education, occupation, mental and physical health and illness, and mortality. Intelligence is one of the most heritable behavioural traits. Here, we highlight five genetic findings that are special to intelligence differences and that have important implications for its genetic architecture and for gene-hunting expeditions. (i) The heritability of intelligence increases from about 20% in infancy to perhaps 80% in later adulthood. (ii) Intelligence captures genetic effects on diverse cognitive and learning abilities, which correlate phenotypically about 0.30 on average but correlate genetically about 0.60 or higher. (iii) Assortative mating is greater for intelligence (spouse correlations ~0.40) than for other behavioural traits such as personality and psychopathology (~0.10) or physical traits such as height and weight (~0.20). Assortative mating pumps additive genetic variance into the population every generation, contributing to the high narrow heritability (additive genetic variance) of intelligence. (iv) Unlike psychiatric disorders, intelligence is normally distributed with a positive end of exceptional performance that is a model for 'positive genetics'. (v) Intelligence is associated with education and social class and broadens the causal perspectives on how these three inter-correlated variables contribute to social mobility, and health, illness and mortality differences. These five findings arose primarily from twin studies. They are being confirmed by the first new quantitative genetic technique in a century-Genome-wide Complex Trait Analysis (GCTA)-which estimates genetic influence using genome-wide genotypes in large samples of unrelated individuals. Comparing GCTA results to the results of twin studies reveals important insights into the genetic architecture of intelligence that are relevant to attempts to narrow the 'missing heritability' gap.

Genetic Predisposition to Disease↗
PubMed1992

Serum cholesterol, triglycerides, and aggression in the general population.

A higher than expected number of violent deaths and suicides in coronary prevention trials has provoked interest in the possibility that low serum cholesterol concentrations are associated in the general population with personality characteristics predisposing to aggressive and suicidal behaviour. We have investigated this possibility in the Edinburgh Artery Study. We measured serum lipid concentrations in blood samples taken from fasting subjects and assessed personality characteristics on the Bedford Foulds Personality Deviance Scales in a random sample of 1592 men and women aged 55-74 years, selected from age-sex registers of ten general practices in Edinburgh. Serum cholesterol concentration was not significantly associated with aggression in men, but it was associated in multivariate analysis (though not univariate analysis) with denigratory attitudes towards others among women. However, serum triglyceride concentration was related, especially in men, to hostile acts (r = 0.13, p < 0.001) and domineering attitude (r = 0.12, p < 0.001) independently of age, total and HDL cholesterol, cigarette smoking, and alcohol consumption. Subjects taking part in prevention trials have higher triglyceride concentrations than the general population and the relation between serum triglyceride concentration and aggression merits further investigation.

Aged↗
PubMed1992

Recombinant erythropoietin improves cognitive function in chronic haemodialysis patients.

Psychometric performance was studied on two occasions in 18 chronic haemodialysis patients. Nine patients treated with rHuEpo performed a battery of psychometric tests before treatment, haemoglobin [mean (SD)] 5.8 (0.6) g/dl and after partial correction of anaemia, haemoglobin 9.3 (1.28) g/dl. The same battery of psychometric tests was administered on two occasions to nine patients (haemoglobin 7.3 (1.2) g/dl) matched with the treatment group for age, educational status and social class, who did not receive rHuEpo. In the rHuEpo-treated group, IQ, measured by the Wechsler Adult Intelligence Scale-Revised, improved by a mean of 8.7 points (P less than 0.01), while in the control group an improvement by a mean of 2.5 points was not significant. Comparison between the groups of the change in IQ score was significant (P = 0.04). There was no change in the mean scores obtained in either group for the other psychometric tests administered including the Paced Auditory Serial Addition Test, Rey auditory verbal learning, and Borkowski verbal fluency test. These results indicate that anaemia makes a reversible contribution to uraemic cognitive dysfunction.

Adult↗
PubMed1992

Effect of therapeutic theophylline levels on the sleep quality and daytime cognitive performance of normal subjects.

The effect of theophylline on sleep quality and cognitive performance in patients with obstructive lung disease has been the subject of controversy. To examine the direct effects of theophylline on sleep quality and cognitive performance, without confounding effects from bronchodilatation, we have undertaken a study of the drug in healthy subjects. A double-blind, placebo-controlled crossover protocol was used to study the effect of oral sustained-release theophylline (Theodur) on subjective sleep quality, objective sleep quality, and cognitive performance. Overnight sleep studies were carried out on Nights 13 and 14 of each 2-wk study limb, and cognitive performance tests administered on Days 1 and 13 of each limb. A total of 18 subjects satisfactorily completed the study (8 males, median age 37, range 24 to 67 yr). Theophylline levels were median 10.2, range 2.3 to 13.3 micrograms/ml on Day 1 and 14.7, range 9.6 to 17.5 micrograms/ml on Day 13. No significant difference was observed between theophylline and placebo on subjective or objective sleep quality or on acute or medium-term cognitive performance. We conclude that theophylline does not affect sleep quality or cognitive performance in normal adults.

Adult↗
PubMed1992

Depression and 'hassles' in globus pharyngis.

A group of 25 patients (16 women, 9 men) attending an ENT department with globus sensation and 25 matched ENT controls were assessed using the Beck Depression Inventory and scales for daily stressful events ('hassles'). Globus patients of both sexes were significantly more depressed than controls and had Beck scores suggestive of significant depression. Thirteen patients, but only two controls, had an independent life event within two months of disease onset, and patients had higher hassles scores than controls.

Adult↗
PubMed1992

Relationships between surgical ability ratings and spatial abilities and personality.

Twenty-two trainee surgeons were tested on high level tests of intelligence, a detailed battery of paper-and-pencil and computerized spatial ability tests, and personality tests. They were also rated for operating ability, clinical decision-making ability, and for overall performance by consultant surgeons who knew them well. Ability ratings were high, indicating very little dissatisfaction with the performance of trainee surgeons. There were no significant correlations between surgical ability ratings and intelligence test scores. The only significant correlation between spatial ability and ability ratings was with one subtest, and was in the opposite direction to that expected. Trends in the data suggested that those trainees rated as superior tended to be more introverted and conscientious, and tended to have better stereoscopic depth perception. The discussion questions the necessity for aptitude testing in surgery and points out some statistical pitfalls in the area. It is concluded that little advance may be made with the application of aptitude testing in the selection of surgeons until there are more objective criteria of surgical ability in different surgical specialties.

Adult↗
PubMed1991

Cumulative cognitive impairment following recurrent severe hypoglycaemia in adult patients with insulin-treated diabetes mellitus.

To examine the hypothesis that episodes of severe hypoglycaemia may cause cumulative cognitive impairment. 100 Type 1 (insulin-dependent) diabetic patients were examined. Their age range was 25-52 years, and the onset of diabetes had occurred after the age of 19 years. Patients with evidence of organic brain disease, including cerebrovascular disease, were excluded. A questionnaire was used to assess the number, frequency and severity of hypoglycaemic episodes experienced during treatment with insulin and the accuracy of this retrospective information was verified from general practice and hospital case-notes. A detailed neuropsychological assessment was undertaken, including tests of pre-morbid and present IQ (Wechsler-Revised), memory and information-processing speed. Significant correlations were observed between the frequency of severe hypoglycaemia and the magnitude of intellectual decline, Performance IQ, inspection time and reaction time (patients with the more frequent hypoglycaemia had poorer performance). Two sub-groups of patients were identified on the basis of their experience of severe hypoglycaemia, and were balanced for pre-morbid IQ, age and duration of diabetes. One sub-group (n = 23) had never experienced severe hypoglycaemia (Group A), whilst the other sub-group (n = 24) had suffered at least five episodes of severe hypoglycaemia (Group B). Group B had greater intellectual impairment than Group A, and Group B also had a significantly slower mean reaction time and higher reaction time variance when compared with Group A.

Adult↗
PubMed1991

Depression, hassles and somatic symptoms in mandibular dysfunction syndrome patients.

Thirty-seven patients with mandibular dysfunction syndrome (MDS) and 30 age-, sex- and education-matched dental outpatient controls were assessed using the Beck Depression Inventory, the Hassles Scale and a symptom checklist derived from the DSM-III criteria for somatization disorder. MDS patients had higher levels of depressive symptoms than control patients (P less than 0.05), though only five out of 37 (13.5 per cent) of the MDS patients had depression intensity levels suggesting clinically significant psychopathology. No significant differences were found between MDS patients and controls on the Hassles Scale, which fails to support the stress-induced muscular hyperactivity theory for the aetiology of MDS syndrome. MDS patients reported having a past history of more somatic symptoms than did controls (P less than 0.05). MDS patients were divided by a clinician into 'physical' and 'functional' groups based on their clinical history. Contrary to expectation, there were no between-group differences on any of the above-mentioned psychological variables.

Adult↗
PubMed1991

Inspection time, psychometric intelligence and clinical estimates of cognitive ability in pre-senile Alzheimer's disease and Korsakoff's psychosis.

Ten pre-senile Alzheimer's patients, 11 patients with Korsakoff's psychosis and 11 age- and pre-morbid intelligence-matched controls were given a test of Inspection Time, which estimates the efficiency of visual encoding or iconic memory. Alzheimer's patients had impaired Inspection Time while the Korsakoff group performed very similarly to the controls. Inspection Time performance correlated significantly with psychometric tests of cognitive ability and with clinical tests of cognitive ability (Mini Mental State Examination and Cambridge Mental Disorders of the Elderly Examination). The early stage of information processing measured by the Inspection Time procedure appears to be damaged by the Alzheimer's disease process, and to impose a rate-limiting effect on a wide variety of mental tests.

Alcohol Amnestic Disorder↗
PubMed1991

The effects of captopril vs atenolol on memory, information processing and mood: a double-blind crossover study.

1. Measures of memory, information processing ability, mood states and trait anxiety were estimated in a double-blind, double-dummy, randomised cross-over trial which compared the effects of atenolol (50 or 100 mg once daily) and captopril (25 or 50 mg twice daily), each taken for 6 weeks. Eighteen patients with mild to moderately severe hypertension were included. 2. There were no significant differences in systolic or diastolic blood pressure reduction between the two drugs. Pulse rate was slower after atenolol treatment (P less than 0.05). 3. Patients undertook practice on the psychological test battery prior to the treatment phases of the study in order to minimise practice effects. 4. There were no significant differences between the treatments on any of the measures of memory or information processing. 5. Patients reported feeling less anxious during treatment with atenolol (P = 0.02). 6. There were no differences between the drugs in their cognitive effects. The present study has the advantages of using an extensive battery of standard tests in a group of well-practised patients. The decreased anxiety reported with atenolol treatment may have clinical value and probably reflects the well-known effect of beta-adrenoceptor antagonist drugs on the somatic symptoms of situational anxiety.

Adult↗
PubMed1991

The persistence of symptoms in patients with globus pharyngis.

A follow-up study of 104 patients with globus sensation was performed by postal questionnaire. All were asked to complete the Eysenck Personality Questionnaire (EPQ) and a 12-item Throat Symptom Questionnaire. Seventy-two of these patients were sent a follow-up General Health Questionnaire (GHQ). Replies were received from 89 patients (86%), 68 females and 21 males, a mean of 31 months after initial presentation. The feeling of something stuck in the throat had disappeared completely in 27% of patients, but only 4% were never aware of the throat. Throat symptoms showed a reduction with increasing age, but not with increasing interval since presentation. The 15 patients initially treated with antacid therapy had significantly greater dyspepsia scores at review than untreated patients, but no other difference was found between the two groups. GHQ scores showed a small but significant reduction over time. Of EPQ parameters, only the lower lie score in female patients showed any significant difference on repeat testing. Those with persistently high throat scores had significantly lower EPQ lie scores and a trend towards higher GHQ scores at follow-up. None of the psychological parameters measured at the first interview was found to be of prognostic significance. We conclude that, although there is a reduction in occult psychiatric morbidity in patients with the globus sensation over time, underlying personality traits remain stable and that there is a remarkable persistence of pharyngeal symptoms.

Antacids↗
PubMed1991

Morbidity in nocturnal asthma: sleep quality and daytime cognitive performance.

Most patients with asthma waken with nocturnal asthma from time to time. To assess morbidity in patients with nocturnal asthma nocturnal sleep quality, daytime sleepiness, and daytime cognitive performance were measured prospectively in 12 patients with nocturnal asthma (median age 43 years) and 12 age and intellect matched normal subjects. The median (range) percentage overnight fall in peak expiratory flow rate (PEF) was 22 (15 to 50) in the patients with nocturnal asthma and 4 (-4 to 7) in the normal subjects. The patients with asthma had poorer average scores for subjective sleep quality than the normal subjects (median paired difference 1.1 (95% confidence limits 0.1, 2.3)). Objective overnight sleep quality was also worse in the asthmatic patients, who spent more time awake at night (median difference 51 (95% CL 8.1, 74) minutes), had a longer sleep onset latency (12 (10, 30) minutes), and tended to have less stage 4 (deep) sleep (-33 (-58, 4) minutes). Daytime cognitive performance was worse in the patients with nocturnal asthma, who took a longer time to complete the trail making tests (median difference 62 (22, 75) seconds) and achieved a lower score on the paced serial addition tests (-10 (-24, -3)). Mean daytime sleep latency did not differ significantly between the two groups (2 (-3, 7) minutes). It is concluded that hospital outpatients with stable nocturnal asthma have impaired sleep quality and daytime cognitive performance even when having their usual maintenance asthma treatment.

Adult↗
PubMed1991

Symptoms of acute insulin-induced hypoglycemia in humans with and without IDDM. Factor-analysis approach.

OBJECTIVE: This study allocated the symptoms identified during acute hypoglycemia objectively to the autonomic or neuroglycopenic groups of symptoms by the use of factor analysis. RESEARCH DESIGN AND METHODS: Twenty-five nondiabetic subjects, 14 newly diagnosed insulin-dependent diabetic patients, and 16 insulin-dependent diabetic patients with diabetes greater than 4 yr duration were studied. Acute hypoglycemia was induced with insulin (2.5 mU.kg-1 body wt.min-1 i.v.), and symptoms of hypoglycemia were recorded with a seven-point scale at regular time points throughout the studies. Factor analysis of the symptom scores at the time of the acute autonomic reaction with principal component analysis followed by Varimax rotation was used to separate those symptoms that might belong to neuroglycopenic and autonomic groups. RESULTS: Hypoglycemia was induced to a mean +/- SE plasma glucose nadir of 1.3 +/- 0.1 mM in nondiabetic subjects, to 2.0 +/- 0.3 mM in newly diagnosed diabetic patients, and 1.4 +/- 0.2 mM in patients with diabetes of greater than 4 yr duration. The most frequently reported autonomic symptoms were sweating, trembling, and warmness, and the most frequently reported neuroglycopenic symptoms were inability to concentrate, weakness, and drowsiness. Neuroglycopenic symptoms were reported more commonly at the onset of hypoglycemia, which was identified by the development of symptoms. Factor analysis grouped trembling, anxiety, sweating, warmness, and nausea together, and this grouping was labeled an autonomic factor. A second factor was identified that included dizziness, confusion, tiredness, difficulty in speaking, shivering, drowsiness, and inability to concentrate, which was labeled a neuroglycopenic factor. CONCLUSIONS: This study demonstrated the high frequency with which neuroglycopenic symptoms occur at the onset of hypoglycemia and the symptoms that could be used by an individual patient as a warning of the development of acute hypoglycemia, although the rapid reduction of plasma glucose is faster than experienced by the ambulant diabetic patient. Factor analysis assisted with the allocation of symptoms to either the autonomic or neuroglycopenic groupings, but the allocation of some symptoms remained undefined, and care must be taken when assessing symptoms such as hunger, weakness, blurred vision, and drowsiness when comparing the frequency of autonomic versus neuroglycopenic symptoms. To reduce the confusion resulting from the use of different symptom questionnaires in studies of hypoglycemia, a sample questionnaire is presented, the development of which was assisted by our analysis.

Adult↗
PubMed1991

A role for aptitude testing in surgery?

Recent interest in the selection of surgical trainees has been directed towards the use of aptitude tests. Using mainly senior surgeons' ratings of trainees' surgical ability for comparison, specific areas of objective investigation have included manual dexterity, spatial ability, personality, and decision-making ability. While certain spatial ability tests have been shown to correlate with ratings of surgical skill, tests of manual dexterity have not. Personality variables, specifically, show how surgeons deal with stress and decision-making ability, and are considered to be important within the profession. Although aptitude tests are being used in medical recruitment, there is still widespread disagreement over their inclusion and their validity. It is proposed that the use of aptitude testing in surgery is limited by three principal factors: there are too few well-designed studies investigating the basic psychological and psychomotor abilities considered to be specific to surgical skill; the use of subjective ratings of surgical ability as the independent variable in most studies; and the fact that, as yet, there is no working definition of superior surgical ability.

Aptitude Tests↗
PubMedDate not supplied

Classification of symptoms of hypoglycaemia in insulin-treated diabetic patients using factor analysis: relationship to hypoglycaemia unawareness.

The allocation of some symptoms of acute hypoglycaemia to autonomic and neuroglycopenic groups has proved problematical, with possible misinterpretation of studies which depend upon the use of diverse symptom questionnaires. Two hundred and ninety-five randomly selected insulin-treated diabetic patients were asked to report the symptoms which they usually experienced and believed to be caused by hypoglycaemia. Sweating, trembling, inability to concentrate, weakness, hunger and blurred vision were the most frequently reported symptoms. To classify symptoms of hypoglycaemia objectively, Factor Analysis was used to identify related symptoms which grouped together. This resulted in five groups or clusters of symptoms, four of which could be denominated as groups with a presumed common aetiology, and were labelled: 'neuroglycopenic', 'general malaise', 'autonomic', 'motor dysfunction', and 'sensory dysfunction'. The groups of symptoms derived by Factor Analysis were assessed in relation to partial or absent symptomatic awareness of hypoglycaemia based on historical evidence from the 295 insulin-treated diabetic patients. Neuroglycopenic symptoms were reported more commonly by the patients who had reported partial awareness of hypoglycaemia (number of symptoms 2.6 +/- 1.8 (mean +/- SD] than by the patients who had reported normal hypoglycaemia awareness (1.4 +/- 1.5 symptoms) (p less than 0.05). By contrast autonomic symptoms were reported less frequently by the patients who had reported absent hypoglycaemia awareness (1.3 +/- 1.4 symptoms) than by those with normal awareness (2.2 +/- 1.4 symptoms) (p less than 0.05), which was similar to the number of autonomic symptoms reported by the patients who had partial hypoglycaemia awareness (2.1 +/- 1.3 symptoms).

Analysis of Variance↗