Biomedical subjects

A C Parrott

Publications and source records attributed to A C Parrott.

At least 55 records · Page 3Linked to original sources

PubMed1994

Anabolic steroid use by amateur athletes: effects upon psychological mood states.

Twenty-one male amateur athletes attending a Welsh needle-exchange clinic, were asked to complete the Buss-Durke Inventory on feelings of hostility/aggression, and a feeling state questionnaire. All were weight training in local gyms in order to increase their body mass. They were also using high doses of anabolic steroids during 6-14 week cycles, while between these cycles they were steroid free. Subjects reported significantly higher feelings of aggression, aggression towards objects, verbal aggression, and aggression during training (but not physical aggression towards people), during the on-steroid periods. Other changes on-drug, included significantly higher feelings of alertness, irritability, anxiety, suspiciousness, and negativism. While increased aggressiveness has been noted in many previous studies, the present findings demonstrate that anabolic steroids can affect a wide range of psychological mood states.

Adult↗

PubMed1992

Stress and arousal in sedative and stimulant cigarette smokers.

Self-reported feelings of stress and arousal were assessed in 18 sedative and 9 stimulant smokers, over a typical day of smoking. Prior to each cigarette, self-ratings of stress and arousal were recorded on a brief adjective check list. These self-ratings were then repeated following cigarette smoking. These diary data were split into four blocks to represent: first cigarette of the day, second quartile cigarette, third quartile cigarette, and last cigarette of the day. Analysis of variance revealed significant effects of smoking on both stress and arousal. Self-rated feelings of stress were significantly reduced following cigarette smoking (P less than 0.002); this was found with both subjects groups and across all cigarette blocks. Cigarette smoking also led to increased feelings of arousal (P less than 0.01), although these changes in arousal differed between subject groups (drug x type-of-smoker interaction: P less than 0.03). Stimulant smokers showed higher levels of arousal after smoking, across all four cigarette blocks. Sedative smokers showed a slight increase in arousal only after their first cigarette. These findings were not as predicted by the arousal modulation theory of cigarette smoking, which suggests that changes in stress and arousal are interdependent. Instead they show that smoking affects stress and arousal in quite different ways. Stress and arousal should therefore be recognised as independent dimensions within smoking/nicotine research.

Adult↗

PubMed1992

Cigarette smoking and nicotine gum (0, 2 and 4 mg): effects upon four visual attention tasks.

Sixteen regular smokers, abstinent for 12 h prior to testing, were assessed on a battery of four visual attention tasks: rapid visual information processing (RVIP), letter cancellation, Stroop, and width of attention. Each subject was assessed under four conditions: placebo gum, 2 mg nicotine gum, 4 mg nicotine gum, and cigarette smoking (own brand), with the order of drug administration determined by latin square. Pre-post drug difference scores for letter cancellation response time demonstrated a significant monotonic dose-response function, with significantly faster performance following cigarette than placebo. RVIP response time and target detection were also affected by nicotine. One RVIP task parameter demonstrated a significant monotonic dose-response function, with highest performance under smoking. Other RVIP measures demonstrated curvilinear dose-response functions, with highest performance under nicotine gum, and broadly similar performance after placebo gum and cigarette smoking. Monotonic and inverted-U arousal/performance functions similar to these have been demonstrated in previous research with nicotine. In contrast to the significant changes in sustained attention, neither width of attention nor Stroop task performance (an index of distractability) was affected by nicotine. Resting heart rate and subjective 'need for a cigarette' showed the predicted monotonic dose-response functions following nicotine. There were no significant changes in any Profile of Mood State factor.

Adolescent↗

PubMed1989

Nicotine chewing gum (2 mg, 4 mg) and cigarette smoking: comparative effects upon vigilance and heart rate.

Sixteen male smokers, abstinent the morning before testing, were assessed under four conditions: placebo chewing gum, 2 mg nicotine chewing gum, 4 mg nicotine gum, and cigarette smoking. Placebo gum was administered in the cigarette condition, while sham smoking occurred in the gum conditions. Pre-drug administration and post-drug difference scores were calculated for each assessment measure: rapid visual information processing (RVIP), memory for new information, and heart rate. Nicotine raised heart rate in a significant monotonic dose-related manner (P less than 0.001): placebo +0.2; 2 mg gum +5.1; 4 mg gum +9.8; cigarette +17.5 bpm. Rapid visual information processing target detections were also significantly related to dose (P less than 0.01), with this increased vigilance significant under 4 mg nicotine gum and cigarette smoking. Memory task performance was not significantly affected. Self-reported feelings of alertness/energy were higher while smoking than under placebo or 4 mg gum. Complaints about the taste of the 4 mg nicotine gum were frequent.

Adolescent↗

PubMed1989

Transdermal scopolamine: a review of its effects upon motion sickness, psychological performance, and physiological functioning.

Scopolamine is the most effective single drug for the prophylaxis and treatment of motion sickness. However, oral or injected scopolamine displays a comparatively short duration of action (5-6 hours), and leads to deleterious side effects on autonomic and central nervous system cholinergic functions. The transdermal scopolamine system was designed to reduce these problems, but while it does deliver scopolamine over a prolonged time period (72 h), deleterious side effects are also produced. Transdermal scopolamine provides significant motion sickness protection, similar in extent to that provided by oral scopolamine or dimenhydrinate. Its autonomic nervous system effects comprise reduced salivation, bradycardia, and blurred vision due to reduced visual accommodation. The visual problems increase following repeated patch applications, with hypermetropic ("long sighted") individuals particularly at risk. Central nervous system effects comprise reduced memory for new information, impaired attention, and lowered feelings of alertness. Variation in response to transdermal scopolamine has also been reported, both between individuals, and between different patch applications on the same individual.

Accommodation, Ocular↗

PubMed1987

Promethazine, scopolamine and cinnarizine: comparative time course of psychological performance effects.

Single oral doses of promethazine (12.5 mg, 25 mg), scopolamine (0.6 mg), and cinnarizine (30 mg), were compared in a double-blind, placebo controlled trial. Twelve normal volunteers undertook a battery of psychological performance tests and a feeling state questionnaire, before drug administration, and at 2-h intervals after. Promethazine and cinnarizine significantly impaired psychomotor performance, information processing and feelings of alertness. With promethazine these reductions were maximal 3-4 h post-drug, with performance returning near to baseline 8-9 h post-drug. With cinnarizine these impairments were maximal 5-6 h post-drug, and performance remained depressed 8-9 h post-drug. Scopolamine significantly reduced feelings of alertness, and memory task performance; the overall performance effects were most evident 1-4 h post-drug.

Adolescent↗

PubMed1987

Transdermal scopolamine: effects of single and repeated patches upon psychological task performance.

Scopolamine and placebo transdermal patches were applied on alternating days to 12 normal volunteer subjects. Psychological performance tasks, physiological assessments, a subjective feeling state questionnaire, and a sleep questionnaire were completed each day. Transdermal scopolamine produced significant decrements in memory task performance, daytime feelings of alertness, ease of waking, and alertness following waking, while resting heart rates were lowered. Significant drug x patch number interaction effects were present with memory for new information, letter cancellation omission errors, rapid visual information processing reaction time, and self-rated ease of getting to sleep, but there was no consistent pattern to the changes following successive patches. Visual problems (blurred vision, longer visual near point) increased following successive scopolamine patches, but the changes in task performance were not related to these visual changes.

Administration, Cutaneous↗

PubMed1986

The effects of transdermal scopolamine and four dose levels of oral scopolamine (0.15, 0.3, 0.6, and 1.2 mg) upon psychological performance.

Four dose levels of oral scopolamine (0.15 mg, 0.3 mg, 0.6 mg, 1,2 mg), transdermal scopolamine, and placebo, were investigated for their effects upon a battery of psychological performance measures in normal subjects. Oral scopolamine produced significant linear dose-related decrements on tasks involving continuous attention, continuous performance, memory storage for new information, and on self-rated feelings of alertness and sociability. Transdermal scopolamine produced significant performance impairments on these same assessment measures. Resting heart rate levels were significantly reduced by all scopolamine conditions. Side effects (dry mouth, dizziness) were frequent following transdermal scopolamine and the higher oral dose conditions. The overall effects of the transdermal scopolamine patch were broadly equivalent to the effects of 0.8 mg oral scopolamine. This oral dose equivalence for transdermal scopolamine is higher than expected, and possible reasons for this are discussed.

Administration, Oral↗

PubMed1985

Effects of transdermal scopolamine upon psychological test performance at sea.

The effects of transdermal scopolamine upon objective psychological performance assessments and self reports of feeling states, were investigated with volunteer subjects at sea. Scopolamine and placebo patches were administered on consecutive days in a counterbalanced order. Psychological performance was assessed 24 h following each transdermal patch. Choice reaction time and code substitution performance levels were not significantly changed, but letter cancellation errors were significantly more frequent following transdermal scopolamine. Transdermal scopolamine caused significantly more reports of dry mouth. More subjects were also unable to undertake the performance tests following scopolamine than placebo, due to difficulties in focusing on the test materials. However despite deleterious side effects with some personnel, others responded positively to the scopolamine patch. As noted by other workers, responses to the transdermal scopolamine patch seem to be quite variable.

Adolescent↗

PubMed1983

Effects of a 1,5-benzodiazepine derivative upon performance in an experimental stress situation.

Psychological performance tasks were given to normal subjects under different conditions of experimental stress: high stress (being filmed on video), or low stress (tested without filming); and after different pharmacological treatments: clobazam 20 mg (an anxiolytic 1,5-benzodiazepine derivative), or placebo. On all five performance assessments (choice reaction times, serial subtraction times, critical flicker fusion values), there was a consistent tendancy for clobazam performance to be comparatively better under high stress, and for placebo performance to be comparatively better under low stress. From these, and previous similar findings, it seems that the level of experimental "stress" under which subjects are tested, can have important influences upon the psychopharmacological performance levels obtained.

Adult↗

PubMed1982

Personal constructs of anxiety under the 1,5-benzodiazepine derivative clobazam related to trait-anxiety levels of the personality.

In an initial interview, 20 volunteer subjects provided 32 personal constructs of anxiety, using Kelly's repertory grid technique. The bipolar ends of the anxiety constructs were then separated by 10-point rating scales. Subjects could then indicate the degree of anxiety feeling on their own personal constructs. The 20 subjects were divided into high and low trait-anxiety sub-groups, on the basis of Speilberger trait-anxiety (personality) scores. Subjects were administered acute single doses of 20 mg clobazam or matching placebo, in a counterbalanced double-blind design. Anxiety levels on the individual personal constructs of anxiety were measured 2 h after drug administration. There was a significant ANOVA interaction effect between drug condition and trait-anxiety. Of the ten subjects in the high trait-anxiety sub-group, eight demonstrated reduced levels of personal construct anxiety under clobazam (three significantly). In contrast, of the ten subjects in the low trait-anxiety sub-group, nine demonstrated increased levels of personal construct anxiety (eight significantly). The present results are discussed in relation to previous similar findings. Clobazam and other benzodiazepine derivatives (such as diazepam) are effective anxiolytics with the clinically anxious and with normal volunteers having high trait-anxiety personalities. However, normal subjects with low trait-anxiety personalities often produce paradoxical increases in anxiety feelings.

Adolescent↗

PubMed1982

Nomifensine, clobazam and HOE 8476: effects on aspects of psychomotor performance and cognitive ability.

The effects of a combination of nomifensine and clobazam (HOE 8476) were compared, on a variety of psychometric measures, with those of its separate monosubstances in a placebo controlled double-blind study with twelve normal volunteers. Assessments comprised a range of psychomotor performance tests, measures of cognitive processing ability and visual analogue rating scales - previously shown to be sensitive to the effects of psychotropic drugs. Subjects acted as their own control and were tested in the morning and afternoon following subchronic pre-dosing with each of the four treatments. When compared with placebo, nomifensine showed no significant change on any of the performance measures. HOE 8476 produced no significant changes in performance but significantly reduced self-rated anxiety. Clobazam significantly improved subjective ratings of the ease of getting to sleep and impaired choice reaction time and concept identification performance in the morning. No significant changes in the test measures were found in the afternoon following any treatment. The findings were in broad agreement with those of previous studies and demonstrated that clobazam and nomifensine, both alone and in combination, tended not to impair performance on a wide range of psychological test assessments.

Adult↗

PubMed1980

The Leeds Sleep Evaluation Questionnaire in psychopharmacological investigations - a review.

The Leeds Sleep Evaluation Questionnaire comprises ten self-rating 100-mm-line analogue questions concerned with aspects of sleep and early morning behaviour. The questionnaire has been used to monitor subjectively perceived changes in sleep during psychopharmacological investigations involving a variety of psychoactive agents, including sedative-hypnotics, antidepressants, anxiolytics, CNS stimulants, and antihistamines. Dose-related improvements in the self-reported ratings of getting to sleep and perceived quality of sleep were generally associated with reductions in the self-reported levels of alertness and behavioural integrity the morning following the nocturnal administration of sedative hypnotic and anti-anxiety agents. Psychostimulants on the other hand, impaired subjective ratings of sleep and produced increases in early morning assessments of alertness. Certain antidepressant and antihistaminic agents produced effects similar to the sedative-hypnotics, while others did not affect self-reported aspects of sleep and early morning behaviour.

Adolescent↗

PubMed1980

The effects of combined sedative and anxiolytic preparations on subjective aspects of sleep and objective measures of arousal and performance the morning following nocturnal medication. I: Acute doses.

Acute doses of various sedative and anxiolytic preparations were administered to consenting volunteers and the effects measured on both subjective and objective assessments of sleep and early morning behaviour. Nitrazepam was used as the benzodiazepine hypnotic, dichloralphenazone as the standard non-benzodiazepine hypnotic and clobazam as the representative anxiolytic preparation. The acute dose nature of the study produced variable results, but a degree of disruption of performance the morning following nocturnal medication was measured. This suggested that anxiolytics and sedatives might potentiate one another and the resulting disorganisation of behaviour might be important in patient populations having to drive motor vehicles.

Adult↗

PubMed1980

The effects of combined sedative and anxiolytic preparations on subjective aspects of sleep and objective measure of arousal and performance the morning following nocturnal medication. II. Repeated doses.

The previous acute dose study showed various combinations of sedatives and anxiolytics to be effective in improving sleep but disrupting some aspects of behaviour the morning following. Repeated doses of similar combinations show that all active preparations improve the subjective assessments of sleep. Some established hypnotics (amylobarbitone sodium) show a hangover the morning following while some anxiolytic/sedative combinations (clobazam/dichloralphenazone) show no hangover. This finding suggests that the different drugs have differential modes of action on sleep and early morning behaviour. The uncertainty with which some anxiolytic/sedative combinations interact to change subjective and objective measures warrants further investigation.

Adult↗

PubMed1979

The effects of repeated nocturnal doses of clobazam, dipotassium chlorazepate and placebo on subjective ratings of sleep and early morning behaviour and objective measures of arousal, psychomotor performance and anxiety.

1. Repeated nocturnal doses of 30 mg clobazam and dipotassium chlorazepate 15 mg showed no significant effects compared to matching placebo on tests of psychomotor performance and serial subtraction of numbers given in the morning and afternoon of the day following treatment. 2. Both active preparations improved the perceived quality of sleep compared to placebo. 3. A reduction in rated anxiety scores was found with clobazam on the afternoon of the day following treatment together with an elevation of critical flicker fusion thresholds. 4. Dipotassium chlorazepate was found to impair performance of a low level conceptual task but not to influence performance at a more difficult level.

Adult↗

PubMed1978

Factor analysis of a sleep evaluation questionnaire.

A self-completion sleep evaluation questionnaire (SEQ), consisting of 10 cm line analogue rating scale questions, was constructed to investigate subjects' responses to aspects of sleep and early morning behaviour. The questions were grouped into 4 chronological areas: the ease of getting to sleep (GTS), the perceived quality of sleep (QOS), the ease of awakening from sleep (AFS), and the integrity of early morning behaviour following wakefulness (BFW). Five hundred and one SEQs were completed during several investigations into the comparative effectiveness of hypnotic drugs. The classical factor analysis produced 4 factors which corresponded to the 4 aspects of sleep and early morning behaviour listed above. The GTS and QOS factors were positively correlated (+0.57), as were the AFS and BFW factors (+0.48). The 2 sleeping state factors (GTS and QOS) were orthogonal to the 2 waking state factors (AFS and BFW).

Adolescent↗

PubMed1978

A repeated dose comparison of the side effects of five antihistamines on objective assessments of psychomotor performance, central nervous system arousal and subjective appraisals of sleep and early morning behaviour.

The side effects of five antihistamines (chlorpheniramine maleate, mebhydrolin, clemastine hydrogen fumarate, Tavegil; ketotifen, and promethazine hydrochloride) were measured on subjective assessments of sleep and the integrity of early morning behaviour and objective assessments of complex psychomotor behaviour and central nervous system arousal. Fifty consenting volunteers each received one of the five preparations for a period of four days with the subjective effects being reported on a set of 10 cm line visual analogue scales and the objective assessments being made via a computer assisted reaction time task and critical flicker fusion thresholds. Chlorpheniramine, 4 mg t.d.s. for four days, produces a significant impairment in critical flicker fusion thresholds with respect to pretreatment baselines but none of the preparations showed any significant impairment in complex reaction time assessments. The subjective assessments of sleep and early morning hangover showed mebhydrolin and clemastine to be free from detrimental side effects, but promethazine and chlorpheniramine produce significant impairments in the integrity of early morning behaviour.

Adult↗