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A C Parrott

Publications and source records attributed to A C Parrott.

At least 37 records · Page 2Linked to original sources
PubMed2002

Recreational Ecstasy/MDMA, the serotonin syndrome, and serotonergic neurotoxicity.

The ring-substituted amphetamine derivative 3,4-methylenedioxymethamphetamine (MDMA) or "Ecstasy" is widely used a recreational drug. It stimulates the release and inhibits the reuptake of serotonin (5-HT) and other neurotransmitters such as dopamine to a lesser extent. The acute boost in monoamine activity can generate feelings of elation, emotional closeness, and sensory pleasure. In the hot and crowded conditions of raves/dances, mild versions of the serotonin syndrome often develop, when hyperthermia, mental confusion, and hyperkinesia predominate. Rest in a cooler environment generally reverses these problems, although they can develop into medical emergencies, which occasionally prove fatal. This acute serotonergic overactivity is exacerbated by the high ambient temperatures, overcrowding (aggregate toxicity), and use of other stimulant drugs. The on-drug experience is generally followed by negative moods, with 80--90% of weekend Ecstasy users reporting 'midweek blues', due probably to monoaminergic depletion. Single doses of MDMA can cause serotonergic nerve damage in laboratory animals, with repeated doses causing extensive loss of distal axon terminals. Huether's explanatory model for this 5-HT neurotoxicity will be briefly described. There is an increasing body of evidence for equivalent neuropsychobiological damage in humans. Abstinent regular Ecstasy users often show: reduced cerebrospinal 5-HIAA, reduced density of 5-HT transporters, blunted response to a fenfluramine challenge, memory problems, higher cognitive deficits, various psychiatric disorders, altered appetite, and loss of sexual interest. Functional deficits may remain long after drug use has ceased and are consistent with serotonergic axonal loss in higher brain regions.

Animals↗
PubMed2001

Recreational ecstasy/MDMA and other drug users from the UK and Italy: psychiatric symptoms and psychobiological problems.

RATIONALE: Recreational drug use is increasingly widespread amongst young people, but there are concerns that psychoactive drugs may be associated with psychiatric symptoms or psychobiological problems. OBJECTIVES: To assess the psychiatric health status of a large, non-clinical sample of young adults from Italy and the UK, and relate it to their use of ecstasy/MDMA and other recreational drugs. METHODS: The UEL Recreational Drug Use Questionnaire was completed by 768 young people (mean age 21.7 years) from four European cities. The subjects comprised 150 non-drug users, 185 alcohol/tobacco users, 97 cannabis and alcohol/tobacco users, 102 illicit polydrug but not ecstasy users, 115 light (<20 times) ecstasy polydrug users, and 119 heavy (>20 times) ecstasy polydrug users. The unpaid volunteers completed the SCL-90 self-rating inventory for psychiatric symptoms when off drug, with 30 additional questions covering positive moods and life experiences. RESULTS: Heavy ecstasy polydrug users reported significantly higher scores than non-drug users on several SCL-90 factors, including phobic anxiety, obsessive-compulsive behaviour, anxiety, psychoticism, somatisation, and significantly higher rates of 'loss of sex interest or pleasure'. Self-rated symptom scores increased in line with greater drug use, so that polydrug users who had never taken ecstasy also reported a variety of psychobiological impairments. In contrast, positive moods and life experiences were broadly similar across subgroups. CONCLUSIONS: The recreational use of ecstasy/MDMA is associated with a range of psychiatric symptoms and psychobiological problems. However, these problems are not specific to ecstasy users but are also evident in other recreational polydrug users.

Adolescent↗
PubMed2001

Ecstasy use: cognitive deficits related to dosage rather than self-reported problematic use of the drug.

Previous research has shown drug-free Ecstasy users to demonstrate selective cognitive impairment. However, there seems to be a degree of individual variation in the occurrence of such deficits. The present study aimed to assess whether these cognitive deficits are related to an awareness of problematic Ecstasy use, or to past drug dosage. Twenty regular Ecstasy users who reported experiencing Ecstasy-related problems were compared with 20 Ecstasy users who had not reported any previous problems. The two groups displayed similar past histories in relation to a range of illicit drugs, and were divided into low, medium and high users. The controls comprised 20 illicit recreational drug users who had never taken Ecstasy. Executive task measures comprised the Tower of London (TOL), the Wisconsin Card Sorting Task (WCST) and spatial working memory. Immediate and delayed word recall, matched verbal recognition and recall and simple reaction time were also included. Both Ecstasy groups performed significantly worse than controls on two executive measures: TOL planning time and spatial working memory score. There were no differences in cognitive impairment between the Ecstasy users who complained of problems and those who did not. In both groups, decrement on executive tasks was demonstrated as a function of previous drug dose. The study confirms that heavy Ecstasy polydrug use may culminate in selective executive deficits. It also demonstrates that two differently self-perceived Ecstasy groups showed similar cognitive impairment, despite only one group complaining of problems. Because all Ecstasy participants also consumed a range of other illicit drugs, the results are reflective of Ecstasy polydrug use in individuals who use Ecstasy as a drug of preference.

Adult↗
PubMed2000

Psychobiological problems in heavy 'ecstasy' (MDMA) polydrug users.

Twelve heavy recreational ecstasy drug users (30-1000 occasions), 16 light ecstasy users (1-20 occasions) and 22 non ecstasy user controls, with group mean ages around 21 years, were compared. Three self-rating questionnaires were completed when drug-free: the SCL-90 (an outpatient psychiatric symptom checklist), the impulsiveness venturesomeness and empathy (IVE) scale; and the uplifts, hassles, stresses and cognitive failures questionnaire. Heavy Ecstasy users reported significantly higher scores than controls on the following SCL-90 factors: paranoid ideation, psychoticism, somatisation, obsessionality, anxiety, hostility, phobic anxiety, altered appetite and restless sleep, together with greater IVE impulsiveness. Light ecstasy users generally produced intermediate scores, with significantly higher scores than controls on two factors and significantly lower scores than heavy ecstasy users on another two. Previous reports have described various psychiatric and psychobiological disorders in recreational ecstasy users, but it is not known how typical they are, being mainly based on individual case studies. This is the first study to describe psychological problems in a non clinical sample of young recreational ecstasy users. However, our ecstasy users were polydrug users, with both groups showing significantly greater usage of amphetamine, LSD and cocaine, than the controls. These other illicit drugs probably contributed to their adverse psychobiological profiles, while there is also the possibility of pre-existing differences between ecstasy users and non users. However, since repeated MDMA can cause serotonergic neurotoxicity in laboratory animals and man, these problems may reflect reduced serotonin activity induced by regular ecstasy use.

Adolescent↗
PubMed2000

Human research on MDMA (3,4-methylene- dioxymethamphetamine) neurotoxicity: cognitive and behavioural indices of change.

Laboratory animals can develop serotonergic neurotoxicity after repeated doses of 3,4-methylenedioxymethamphetamine (MDMA) or 'Ecstasy'. If similar neural damage occurs in humans, this may be evident in cognitive or behavioural impairments. In a review of the behavioural skills shown by drug-free recreational Ecstasy users, three aspects of cognitive performance are often affected: reduced memory for new information (Rivermead Behavioral Memory, supraspan word recall), impaired higher executive processing (Wisconsin Card Sort, Tower of London), and heightened impulsivity (Impulsiveness, Venturesomeness and Empathy Questionnaire, Matching Familiar Figures test). Performance on other more basic cognitive functions is generally unimpaired (simple reaction time, choice reaction time, number vigilance, Stroop, trail making). Some Ecstasy users also complain of poor memories and/or concentration difficulties, which they attribute to MDMA use. There are many methodological problems and uncertainties with research in this field: non-random allocation of subjects to drug conditions, the deleterious effects of other psychoactive drugs, and the possibility that these adverse profiles reflect pre-existing personality characteristics in Ecstasy users. However, this particular pattern of cognitive decrements in humans, is consistent with the animal data on those brain areas showing serotonergic damage following MDMA: the frontal cortex (impulsivity and higher cognitive impairments), and hippocampus (memory deficits). Finally, this profile of cognitive deficits is also consistent with a hypothetical integrative construct: namely reduced cortical inhibition.

Behavior↗
PubMed2000

'Is MDMA a human neurotoxin?': diverse views from the discussants.

UNLABELLED: Every discussant at the Novartis symposium was invited to submit a 250-word abstract, giving their views upon the question: 'Is MDMA a human neurotoxin?'. These abstracts are presented here. They illustrate a wide range of viewpoints and opinions, as might be expected from experts in such diverse fields: animal neuroscience, human cognitive testing, police pathology laboratory, psychotherapeutic institute and psychiatric hospital. Some abstracts emphasized the methodological weaknesses of the human empirical data: the uncertain nature of 'Ecstasy' tablets, the reliance on self-report data, and the contributory factors of heat, dancing/exertion, poor diet and other illicit drugs. These factors may lead to psychobiological changes, which could be misinterpreted as neural damage. The absence of gliosis in animal models was also noted, which led to suggestions that there might be alternative interpretations for the neural changes which have been observed in rats and monkeys. Others noted the absence of neural/behavioural change following a single Ecstasy tablet, or commented upon the therapeutic benefits of MDMA in a quiet supportive environment. Nevertheless, novel studies from England, Germany, Italy, the Netherlands, Scotland and Wales confirmed and extended the range of cognitive, behavioural, EEG and neurological deficits, displayed by drug-free Ecstasy users. Moreover, these deficits often remained when other illicit drug use was statistically controlled. IN CONCLUSION: If MDMA neurotoxicity in humans is a myth, then it is a myth with a heavy serotonergic component.

Animals↗
PubMed1999

Does cigarette smoking cause stress?

Smokers often report that cigarettes help relieve feelings of stress. However, the stress levels of adult smokers are slightly higher than those of nonsmokers, adolescent smokers report increasing levels of stress as they develop regular patterns of smoking, and smoking cessation leads to reduced stress. Far from acting as an aid for mood control, nicotine dependency seems to exacerbate stress. This is confirmed in the daily mood patterns described by smokers, with normal moods during smoking and worsening moods between cigarettes. Thus, the apparent relaxant effect of smoking only reflects the reversal of the tension and irritability that develop during nicotine depletion. Dependent smokers need nicotine to remain feeling normal. The message that tobacco use does not alleviate stress but actually increases it needs to be far more widely known. It could help those adult smokers who wish to quit and might prevent some schoolchildren from starting.

Adolescent↗
PubMed1999

Daily uplifts, hassles, stresses and cognitive failures: in cigarette smokers, abstaining smokers, and non-smokers.

Cigarette smokers (n = 25), temporarily abstaining smokers (n = 25) and non-smokers (n = 25), self-rated their feelings of stress, arousal and pleasure, every 3 h over a normal day. Then, later in the evening, they rated the hassles, uplifts, stresses and cognitive failures they had experienced during the day. The abstaining smokers reported significantly worse psychological states on every assessment measure, in comparison with both non-smokers and non-deprived smokers. Abstinence thus led to greater stress, lower arousal, less pleasure, more cognitive failures, more hassles and less uplifts. The non-deprived smokers did not differ from the non-smokers on any dependent variable. These findings support the Deprivation Reversal Model, which states that the apparent benefits of smoking only represent the reversal of unpleasant abstinence effects. These data provide no evidence to support the Nicotine Resource Model, which suggests that tobacco smoking can relieve stress and improve cognitive functions. The repetitive use of nicotine by cigarette smokers does not seem to generate any real psychobiological gains or advantages. Instead, dependent smokers need regular hits of nicotine just to remain feeling normal.

Adult↗
PubMed1998

Ecstasy (MDMA) effects upon mood and cognition: before, during and after a Saturday night dance.

Three groups of young people (aged 19-30 years) were compared: 15 regular ecstasy users who had taken MDMA (3,4-methylenedioxymethamphetamine) on ten or more occasions; 15 novice ecstasy users who had taken MDMA on fewer than ten previous occasions; and 15 controls who had never taken MDMA. Each subject completed a cognitive test and mood scale battery four times: an initial drug-free baseline, at a Saturday night dance/club (on-drug), then 2 days later, and 7 days later. On the Saturday night, regular ecstasy users took an average of 1.80 MDMA tablets, novice users took 1.45 MDMA tablets, while controls mostly drank alcohol. The consumption of cannabis and cocaine at the club was similar across groups. All three groups reported positive moods at the dance club (on-drug), although there were borderline trends (P < 0.10) for less sadness/depression in the MDMA subgroups. However 2 days afterwards, the ecstasy users felt significantly more depressed, abnormal, unsociable, unpleasant, and less good tempered, than the controls. Cognitive performance on both tasks (verbal recall, visual scanning) was significantly reduced on-MDMA. Memory recall was also significantly impaired in drug-free MDMA users, with regular ecstasy users displaying the worst memory scores at every test session. This agrees with previous findings of memory impairments in drug-free ecstasy users. Animal data have shown that MDMA can generate long-term serotonergic neurodegeneration in various brain areas, including the hippocampus. The cognitive deficits in drug-free recreational ecstasy users, suggest that MDMA may also be neurotoxic in humans.

Adult↗
PubMed1998

Nesbitt's Paradox resolved? Stress and arousal modulation during cigarette smoking.

Nesbitt's Paradox states that cigarette smoking generates physiological and psychological changes which are normally incompatible, namely increased arousal together with decreased stress. This review confirms these changes, but shows that they are dependent upon various factors, particularly the degree of nicotine deprivation. Thus the relaxant properties of smoking reflect the relief of irritability which develops between cigarettes. The deleterious mood effects of abstinence explain why smokers suffer more daily stress than non-smokers, and become less stressed when they quit smoking. Deprivation reversal also explains much of the arousal data, with deprived smokers being less vigilant and less alert than non-deprived smokers or non-smokers. Nicotine can, however, display genuine stimulant properties, although due to repeated abstinence effects the average arousal level of smokers is generally similar to non-smokers. Mood normalization also explains why nicotine is so addictive, with regular smokers needing nicotine just to "function" normally. Finally, Nesbitt's Paradox also assumes that arousal and emotionality are associated with each other. Yet factor analysis of mood and personality questionnaires shows that these two dimensions are statistically independent, with the stress and arousal changes during smoking also generally uncorrelated. Nesbitt's Paradox is therefore not actually a paradox; it never was a paradox.

Affect↗
PubMed1998

Cognitive performance in recreational users of MDMA of 'ecstasy': evidence for memory deficits.

Cognitive task performance was assessed in three groups of young people: 10 regular users of 3,4-methylenedioxymethamphetamine (MDMA) who had taken 'ecstasy' 10 times or more; 10 novice MDMA users who had taken 'ecstasy' one to nine times; and 10 control subjects who had never taken MDMA. A computerized battery of cognitive tasks (Cognitive Drug Research system) was undertaken on a day when subjects were drug free. Performance on the response speed and vigilance measures (simple reaction time, choice reaction time, number vigilance), was similar across the three subgroups. However on immediate word recall and delayed word recall, both groups of MDMA users recalled significantly less words than controls. Animal research has shown that MDMA can lead to serotonergic neurodegeneration, particularly in the hippocampus and frontal cortex. Although the design of this study was far from ideal, these data are consistent with other findings of memory decrements in recreational MDMA users, possibly caused by serotonergic neurotoxicity.

Adolescent↗
PubMed1995

Stress modulation over the day in cigarette smokers.

This review summarizes the findings from a series of four published studies into the relationship between cigarette smoking and stress. In each study, feelings of anxiety/stress were significantly lower post-smoking than pre-smoking (p < 0.001). However, while moods improved immediately after smoking, mood impairments occurred between cigarettes. This repetitive cycle of mood reversals provides a clear rationale for repetitive/addictive cigarette use. The degree of stress modulation was significantly related to the sedative subscale of the Smoking Motivation Questionnaire (p < 0.01). However, high SMQ sedative subjects reported above-average stress prior to smoking, rather than below-average stress after smoking. Thus stress modulation represented mainly the relief of adverse moods, rather than the attainment of beneficial moods. Deprived smokers reported a diurnal pattern of increasing stress, confirming the deleterious effects of nicotine deprivation. These studies demonstrated the importance of mood control as a motive for smoking. They indicate that smokers gain little real advantage from cigarettes, but smoke mainly to forstall nicotine depletion. The deleterious mood effects of acute nicotine withdrawal also helps explain why, when smokers quit smoking, they experience reduced levels of daily stress.

Adult↗
PubMed1995

Smoking cessation leads to reduced stress, but why?

Recent longitudinal studies have demonstrated that smoking cessation leads to reduced feelings of stress. This finding is not predicted by either of the two main models for smoking behavior. The nicotine resource model (Warburton) states that nicotine is used to cope with external stressors, and predicts that smokers will suffer from increased stress when they quit smoking. The deprivation reversal model (Schachter), suggests that smoking reverses the deleterious effects of deprivation; cessation will then lead to a period of increased stress, followed by a return to baseline. Although the stress/cessation data agree with neither model, they are consistent with a third explanation, namely that smoking causes stress. This model states that acute nicotine deprivation (i.e., between cigarettes) leads to increased stress. Smokers then use cigarettes to reverse these withdrawal effects and "normalize" their mood. This model explains some paradoxical aspects of the smoking/mood relationship. First, why smokers are calmed by smoking, yet report high average levels of stress. Second, why stress levels become reduced after smoking cessation; this is because the former smoker no longer suffers from the adverse mood effects of acute nicotine depletion.

Adaptation, Psychological↗
PubMed1994

Acute pharmacodynamic tolerance to the subjective effects of cigarette smoking.

A brief feeling state questionnaire was completed before and after each cigarette, over a day of smoking. Feelings of stress/anxiety demonstrated a pattern of repetitive vacilation over the day, with high stress before smoking, reduced stress after smoking, and stress levels increasing again between cigarettes. There was no evidence of acute pharmacodynamic tolerance, with cigarettes leading to altered feelings of anxiety/stress over the whole day of smoking. Self-rated feelings of arousal also demonstrated a pattern of vacilation over the day, with low arousal pre-smoking increased arousal post-smoking, but arousal levels reducing again between cigarettes. The ANOVA drug x time interaction was significant, with the greatest arousal change following the first cigarette of the day. However, later cigarettes led to similar amounts of arousal change over the rest of day, thus questioning whether acute pharmacodynamic tolerance was occurring. Instead, the heightened arousal response to the first cigarette of the day may reflect the influence of two other factors. Firstly, overnight deprivation, with the first cigarette of the day leading to the greatest increase in plasma nicotine. Secondly, low early-morning arousal with its associated potential for increased arousal. Overall, therefore, there was little indication of acute pharmacodynamic tolerance to the subjective effects of nicotine. Cigarettes were associated with altered feelings of stress and arousal, over the whole day of smoking.

Adolescent↗
PubMed1994

Individual differences in stress and arousal during cigarette smoking.

Self-rated feelings of stress and arousal were monitored before and after each cigarette, over a day of normal smoking. Subjects comprised 105 unpaid volunteers (65 female, 40 male; mean age 30.4 years; mean consumption 12.4 cigarettes on test day). Feelings of arousal were significantly higher post-smoking than pre-smoking. The degree of arousal change was monotonically related to scores on the smoking motivation questionnaire (SMQ) stimulant subscale, with high stimulant smokers reporting the greatest arousal modulation. However stimulant smokers reported low arousal before smoking, rather than high arousal after smoking. Feelings of stress were significantly lower post-smoking than pre-smoking. The degree of stress change was monotonically related to scores on the SMQ sedative subscale, with high sedative smokers reporting the greatest stress change. This confirms the criterion validity of this second SMQ subscale. However, as with the arousal data, sedative smokers tended to report high stress before smoking, rather than low stress after smoking. Smoking did not therefore produce advantageous post-cigarette feeling states. Instead, mood modulation largely comprised the alleviation of poor psychological states prior to smoking. These stress and arousal changes often occurred simultaneously, against the predictions of the arousal modulation theory. Arousal modulation and stress modulation should therefore be seen as separate and independent processes. Lastly, feelings of stress and arousal fluctuated repeatedly over the day, with improved moods immediately after smoking, but impaired moods developing between cigarettes. These mood reversals provide a clear psychological rationale for the repetitive (addictive) nature of nicotine use.

Adult↗