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Biomedical subjects

K D Bird

Publications and source records attributed to K D Bird.

16 recordsLinked to original sources
PubMed1995

Matching smokers to treatment: self-control versus social support.

This study involved 137 participants who were assessed on 12 relevant predictor variables and then randomly assigned to social support or self-control treatment. Outcome across treatments was predicted by cotinine levels, treatment history, previous abstinence, happiness, self-efficacy, and perceived social support for quitting. Social support treatment was more effective than self-control treatment for participants with high baseline self-control orientation scores and participants with high self-efficacy scores. All other hypothesized Subject x Treatment interaction effects were nonsignificant. The study provided an example of a coherent approach to matching research and demonstrated the difficulty involved in providing treatments that are different enough from each other to benefit different smokers. Matching research has important theoretical value but may have limited potential for improving smoking treatment effectiveness.

Adult↗
PubMed1993

Effects of gender, age and diagnosis on perceived parental care and protection in adolescents.

To assess whether perceived parental care and protection varied according to age and gender of the child and whether they were associated with psychiatric diagnoses, these constructs were measured with the Parental Bonding Instrument in a cohort of non-referred adolescents (n = 762), in a clinically referred cohort (n = 1299), and in a group of adolescents from the referred cohort (n = 365) for whom DSM-III diagnoses were available. Significant differences in parental care and protection according to clinical status, age, gender and diagnosis were found. However, perceived parental affectionless control was not associated with emotional disorders in adolescents, contrary to reports in adult subjects, but with clinical status.

Adolescent↗
PubMed1991

Sex differences in suicidal behaviour of referred adolescents.

Reports of suicidal behaviour from four countries using the same measures were higher for girls than for boys, and higher in self-reports than in parent reports for both referred and normal adolescents. In a sample of 480 referred adolescents, patterns of 'low' and 'high' suicidal scores were different when age, sex and diagnosis were considered. The probability of high scores for girls showed only a marginal increase with age, while there was a striking rise for boys. An affective diagnosis doubled the probability of high scores for both boys and girls, while it had no effect on low scores. Psychosocial stressors also increased the probability of high suicidal scores, particularly in adolescents with an affective disorder. Sex differences in suicidal behaviour were marked in the low-scoring groups.

Adolescent↗
PubMed1990

The effects of orally administered delta 9-tetrahydrocannabinol in man on mood and performance measures: a dose-response study.

A dose-response study of the effect of orally administered delta 9-tetrahydrocannabinol (THC) on human mood and skills performance was conducted. Using five dose levels of THC (0, 5, 10, 15, 20 mg) with 16 volunteers per dosage group, mood and performance measures were recorded at five testing occasions, one before and four after drug administration. The slope of the linear regression of performance on the test battery was significant for up to 200 minutes after dosage. That is to say, oral THC, at the doses used, produced significant dose-dependent impairment of performance for a period in excess of three hours. A similar time course for the effect of THC on the subjective assessment of intoxication ('stone') suggested a correlation between drug-induced impairment skills and the effects on mood.

Administration, Oral↗
PubMed1986

Simultaneous multiple comparison procedures in psychiatric research.

The multiple comparison problem arises in any research design in which the scores of more than two groups are compared on a single dependent variable. The analysis of variance provides a way of testing the null hypothesis that all population means are equal with a type 1 error rate of alpha. When the joint null hypothesis is accepted, the outcome of such a test is unambiguous: all population means are equal. When the null hypothesis is rejected, ANOVA is insufficient to identify the pattern of departure from equality. The Scheffe procedure can be used to test any number and type of contrast that is suggested by an inspection of the data. It ensures that the chance of incorrectly rejecting one or more hypotheses in the set so tested cannot exceed alpha. Contrasts between the population means which are specified independently of the data can be tested using Bonferroni-adjusted t tests to control the experimentwise error rate. Factorial ANOVA designs can also be analysed by testing linear contrasts. If a researcher has definite expectations about the pattern of mean differences, he can test a set of planned contrasts with a familywise error rate (if contrasts are written within main effects and interaction effects) or an EER. If he is uncertain about which hypotheses to test, post hoc procedures which are modifications of the Scheffe technique can be used.

Analysis of Variance↗
PubMed1986

Simultaneous multiple comparison procedures for categorical data.

Methods are outlined for performing simultaneous multiple comparisons between groups when the dependent variable is one in which subjects are assigned to one of two or more categories. These methods provide tests which are analogous to Scheffe- and Bonferroni-adjusted tests of contrasts in the analysis of variance. Examples are provided of each of these procedures.

Analysis of Variance↗
PubMed1986

Statistical power in psychiatric research.

Statistical power is neglected in much psychiatric research, with the consequence that many studies do not provide a reasonable chance of detecting differences between groups if they exist in the population. This paper attempts to improve current practice by providing an introduction to the essential quantities required for performing a power analysis (sample size, effect size, type 1 and type 2 error rates). We provide simplified tables for estimating the sample size required to detect a specified size of effect with a type 1 error rate of alpha and a type 2 error rate of beta, and for estimating the power provided by a given sample size for detecting a specified size of effect with a type 1 error rate of alpha. We show how to modify these tables to perform power analyses for multiple comparisons in univariate and some multivariate designs. Power analyses for each of these types of design are illustrated by examples.

Clinical Trials as Topic↗
PubMed1984

No evidence for a protracted change in endogenous opioid activity following chronic opiate treatment in mice: parallel recovery of cross tolerance to stress and morphine antinociception.

The involvement of central endogenous opioids in swim-induced antinociception in mice is well documented. The response is attenuated by central or systemic naloxone, displays two-way cross tolerance with morphine and is correlated with apparent occupation of central opiate receptors by endogenous ligands. Swim-induced antinociception was utilised as an in vivo model of endogenous opioid function to investigate a possible protracted functional change in endogenous opioid release or inactivation following chronic opiate treatment. Antinociceptive responses (tail-flick latency) to morphine (4.4 mg/kg, SC) and swimming were determined at various times following chronic methadone (24 days treatment, 102 mg/kg day in drinking water for the last 20 days) and chronic morphine (1 g/kg sustained release) treatment. In both experiments, parallel recovery from cross tolerance was observed for morphine-and swim-induced antinociception. These results were consistent with the view that no protracted functional change in the release or inactivation of endogenous opioids had occurred following chronic opiate treatment.

Animals↗
PubMed1984

Investigating drug--ethanol interactions.

Methodology developed in our laboratories for testing the interactive effects of ethanol and drugs on human psychomotor performance is discussed. An attempt has been made to relate the findings of our studies to the results of real-life impairment, particularly in traffic crashes. Proposals for more comprehensive testing of drug--ethanol interactions have been put forward which may increase the predictive value of such tests.

Adult↗
PubMed1982

Naloxone has no effect on ethanol-induced impairment of psychomotor performance in man.

In a study designed to investigate the effect of naloxone on ethanol-induced performance deficits in man, ethanol (0.75 g/kg) and naloxone (0.4 mg) or saline were administered to 39 volunteers in a double-blind fashion. Psychomotor performance was assessed on a battery of tests (standing steadiness, pursuit rotor, simple and complex reaction times, a speeded number test and the Vienna Determination Apparatus) and blood and breath ethanol concentrations were monitored. Two experiments were performed: in Experiment 1 ethanol was given before naloxone and in Experiment 2 naloxone was administered before ethanol. There were no significant differences in either blood or breath ethanol concentrations at any time between the ethanol + naloxone and ethanol + saline groups in either Experiment 1 or 2. Although ethanol produced a significant decrement on most of the performance measures, naloxone was without effect. There was no suggestion of ethanol impairment being moderated by naloxone, whether it was given before or after ethanol.

Adolescent↗
PubMed1981

The correlation between swim-stress induced antinociception and [3H] leu-enkephalin binding to brain homogenates in mice.

Mice which had been made to swim for 3 minutes showed a tail flick latency which was significantly longer than that of unswum controls. The [3H] leu-enkephalin [LE] binding to brain homogenates from swum mice was significantly reduced when compared with that form unswum controls. Scatchard analysis revealed that the reduction in binding occurred at the LE low affinity site. However, when homogenates were allowed a preincubation period of 20 min at 37 degree C, the difference in LE binding between swum and unswum mice was no longer apparent. These data are interpreted to suggest that the reduced LE binding may be due to the occupation of a proportion of the opiate receptor population by an endogenous ligand. A correlation between the duration of the swim induced antinociceptive response and the changes in LE binding is described which although non-significant, is consistent with the interpretation for the involvement of endogenous opiates in the observed increases in tail flick latency.

Animals↗
PubMed1979

The effect of cannabidiol, alone and in combination with ethanol, on human performance.

Fifteen volunteers received cannabidiol (CBD) (320 microgram/kg) or placebo (both orally, T0), and 60 min later they consumed an ethanolic beverage (0.54 g/kg) or placebo. The effects were measured at T1 (100 min after CBD ingestion), T2 (160 min) and T3 (220 min) using cognitive, perceptual and motor function tests. Factorial analysis indicated that test procedures could be adequately expressed by three rotated factors: A reaction speed factor (I), a standing steadiness factor (II) and a psychomotor coordination/cognitive factor (III). Ethanol produced a significant decrement in factor III. There was no demonstrable effect of CBD, either alone or in combination with ethanol. Neither CBD nor ethanol produced any significant effect on pulse rate. Prior administration of CBD did not significantly affect the blood ethanol levels. Whilst the subjects were able to identify correctly when they were given ethanol, they did not report any subjective effects of CBD.

Adolescent↗
PubMed1979

The effect of (-) trans-delta9-tetrahydrocannabinol, alone and in combination with ethanol, on human performance.

Twenty five volunteers received (-) trans-delta9-tetrahydrocannabinol (THC) (320 microgram/kg) or placebo (both orally, T0), and, 60 min later, they consumed an ethanolic beverage (0.54 g/kg) or placebo. The effects of this medication were measured at T1 (100 min after THC ingestion), T2 (160 min), T3 (220 min) and T4 (280 min) using a battery of cognitive, perceptual and motor function tests. Factorial analysis indicated that the test procedures could be adequately expressed by four rotated factors: a reaction speed factor (I'), a cognitive factor (II'), a standing steadiness factor (III') and a psychomotor coordination factor (IV'). The first principal component (I) was used as a measure of general performance across the whole test battery. Both THC and ethanol produced significant decrements in the general performance factor. Ethanol produced significant decrements in standing steadiness and psychomotor coordination, while THC caused a significant deterioration in performance on all the four rotated factors. In all cases the peak effect of ethanol occurred at T1 and by T4 the effect had worn off. The performance decrements induced by THC were slower in onset and lasted longer than those induced by ethanol. In general, the peak effect of THC occurred at T1 and T2. There was no evidence of any interaction between THC and ethanol, and the effects of a combination of THC and ethanol were no more than additive. THC (but not ethanol) produced a significant rise in pulse rate. Prior administration of THC did not significantly affect the blood ethanol levels obtained. The subjects were able to identify correctly which of the treatments they had received.

Adolescent↗