Adverse effects of cannabis and cannabinoids.
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Anesthesia↗
Biomedical subjects
C H Ashton
Publications and source records attributed to C H Ashton.
Structural and functional abnormalities in elderly patients clinically recovered from early- and late-onset depression.
BACKGROUND: Structural and functional brain changes have been described in elderly patients with unipolar affective disorder. Changes appear to be more marked in patients with late-onset depression, but the reversibility of such changes after clinical recovery is not known. METHODS: Magnetic resonance imaging, electroencephalography (EEG), and cognitive tests were performed in 23 elderly patients (mean age 66.5 years) clinically recovered from major depression. Twelve had late-onset depression (first episode over 55 years of age); 11 had early onset (first episode before 50 years). EEG and cognitive testing were also performed on 15 control subjects. RESULTS: Patients with late-onset depression had larger third and lateral ventricles, increased ventricular-brain ratio, and greater frequency and severity of subcortical white matter lesions than those with early onset. There was no difference between early- and late-onset patients in EEG and cognitive measures, but compared with controls patients showed significant changes in EEG evoked potentials and increased slow-wave activity, slowed reaction times, and global impairments in cognitive function. CONCLUSIONS: These results suggest that structural changes are greater in patients with late-onset depression, and that EEG and cognitive impairments persist after recovery, regardless of age of onset of depression, and are independent of structural changes.
Age of Onset↗
An update on British medical students' lifestyles.
Information about medical students' lifestyles was obtained from 785 second-year students from seven medical schools in Great Britain by a personally administered questionnaire. Fifteen per cent of the students were non-drinkers. Among those who drank, 48% of the men and 38% of the women exceeded sensible weekly limits of alcohol consumption, and high-risk levels of consumption were reported by 12% of men and 7% of women. Cannabis had been used at least once or twice by more than half the men and 40% of the women, and 10% reported regular use (weekly or more often). Experience with other illicit drugs was also reported: amphetamines (8% of students), LSD (7%), ecstasy (4%), amyl/butyl nitrate (10%) and magic mushrooms (7%). Nineteen per cent of the students had used two or more different drugs. Experience with illicit drugs started before entering university in more than a third of those who used them. Comparison of the results with other student surveys suggests that the lifestyles of medical students differ little from those of other student groups, but that alcohol and illicit drug consumption is increasing in university students generally. Prospective studies are under way to establish whether medical students change their lifestyles at later stages of their course and after qualification.
Anxiety↗
Assessment of the effects of combination therapy with ciprofloxacin and fenbufen on the central nervous systems of healthy volunteers by quantitative electroencephalography.
The potential effects of concurrent administration of fenbufen and ciprofloxacin on central nervous system activity in healthy young subjects were investigated by electroencephalography (EEG). Visual analog scales (VAS) were used to assess subjective measures of concentration, vigilance, tension, and irritability. When ciprofloxacin was administered in combination with fenbufen, none of the EEG parameters or VAS ratings measured were significantly different from those measured when the drugs were administered alone.
Adult↗
Antidepressant withdrawal syndrome.
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Antidepressive Agents, Second-Generation↗
Alcohol and drug use in UK university students.
BACKGROUND: Alcohol and illicit drug use are increasing among school children and young adults in the UK. Such increases have also been noted among university students and there is a need for a large survey across different universities and faculties. We report such a survey. METHODS: Information about drinking, use of cannabis and other illicit drugs, other lifestyle variables, and subjective ratings of anxiety and depression was obtained by questionnaire in a cross-faculty sample of 3075 second-year university students (1610 men, 1447 women, 18 sex not stated) from ten UK universities. The questionnaire was personally administered during scheduled lecture hours and almost all the students participated. The sample reflected the interfaculty and sex distribution and the proportion of non-white students at UK universities. FINDINGS: 11% of the students were non-drinkers. Among drinkers, 61% of the men and 48% of the women exceeded "sensible" limits of 14 units per week for women and 21 for men. Hazardous drinking (> or = 36 units per week for women, > or = 51 for men) was reported by 15% of the drinkers. Binge drinking was declared by 28% of drinkers. 60% of the men and 55% of the women reported having used cannabis once or twice and 20% of the sample reported regular cannabis use (weekly or more often). Experience with other illicit drugs was reported by 33% of the sample, most commonly LSD (lysergic acid diethylamide), amphetamines, Ecstasy (methylenedioxymethamphetamine), and amyl/butyl nitrate which had each been used by 13-18% of students. 34% of these had used several drugs. Drug use had started at school in 46% of the sample; 13% began after entering university. The overwhelming reason given for taking alcohol or drugs was pleasure. Subjective ratings of anxiety on the hospital anxiety depression scale were high, and sleep difficulties were common, but neither related to alcohol or drug use. INTERPRETATION: There is a need for better education about alcohol, drugs, and general health in universities. Such education should include all faculties. It remains unclear whether university students' lifestyles are carried over into later life.
Adolescent↗
Pharmacokinetics of fluoxetine.
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Drug Interactions↗
Effects of peripherally and centrally acting analgesics on somato-sensory evoked potentials.
1. The effects of aspirin 1000 mg, paracetamol 1000 mg, codeine 60 mg on somatosensory evoked potentials (SEPs) were measured in a four-way cross-over study. 2. SEPs were elicited by electrical stimulation of the skin overlying the digital nerve at intensities close to pain threshold. 3. Amplitudes and latencies of both early and late SEPs were recorded, as well as first sensory threshold and subjective pain threshold. 4. None of the study medications affected the amplitude or latency of the late SEP components (100-250 ms post-stimulus). The amplitude of early components (15-30 ms post-stimulus) was also unaffected, but aspirin shortened the latency 30 min after ingestion. 5. Sensory detection and pain threshold to electrical skin stimulation were also unaffected by any of the study medications despite subjective central effects with codeine.
Acetaminophen↗
Personality, lifestyles, alcohol and drug consumption in a sample of British medical students.
Personality characteristics and lifestyle variables were assessed in two cohorts of second-year medical students at the University of Newcastle upon Tyne, UK as part of a psychopharmacology 'teach-in' in 1993 and 1994. The pooled sample included 186 students: 77 men, 109 women, mean age 20.4 +/- 1.8 years. Measures included the Eysenck Personality Questionnaire, the Hospital Anxiety Depression Scale, and a questionnaire concerning consumption of alcohol, tobacco, cannabis and other illicit drugs, and physical exercise. The results were compared, where possible, with a similar survey in Newcastle upon Tyne medical students in 1983 and 1984. Personality variables, prevalence of cigarette smoking, levels of caffeine consumption and participation in sports had not changed significantly over the decade. There appeared to be a modest overall increase in alcohol consumption and in the 1993 and 1994 cohorts of students, 25.5% of those who drank alcohol exceeded recommended low risk levels (comparable data not available for 1983 and 1984). Reported use of cannabis and other illicit drugs had more than doubled, and in the present survey 49.2% of students recorded using cannabis and 22% had tried other illicit drugs. Corresponding figures for 1983 and 1984 were 20.9% for cannabis and 3.3% for other illicit drugs. Anxiety levels were not measured in 1983 and 1984 but in the present survey 39.3% of the students had anxiety ratings within the clinically significant range. The high levels of alcohol consumption and illicit drug use, and the high anxiety ratings, in this sample of medical students are a cause for concern.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Do cholesterol-lowering agents affect brain activity? A comparison of simvastatin, pravastatin, and placebo in healthy volunteers.
1. The effects of simvastatin and pravastatin on measures of central nervous system activity were investigated in a double-blind, placebo-controlled, randomised crossover study. 2. Twenty-five healthy volunteers sequentially took 40 mg day-1 simvastatin, 40 mg day-1 pravastatin or placebo for 4 weeks, separated by a 4-6 week washout phase. 3. CNS measures included EEG evoked potentials, power spectral analysis, Leeds Sleep Questionnaire, Hospital Anxiety Depression (HAD) Scale, and Digit Symbol Substitution Test (DSST); biochemical measures included plasma cholesterol, liver enzymes (gamma-GT, AST, ALT) and creatine kinase. 4. Mean cholesterol concentrations with both drugs were significantly lower than with placebo, and the cholesterol-lowering effect was greater with simvastatin. There were no significant differences between treatment in EEG evoked potentials, HAD Scale, or DSST scores. On the sleep measure, subjects reported significantly greater difficulty in getting to sleep while on simvastatin than on pravastatin, but neither score differed from placebo. No significant correlations were observed between sleep ratings and either plasma cholesterol concentrations or EEG evoked potentials. 5. The study showed that, while both drugs reduced plasma cholesterol concentrations, neither exerted significant effects, compared with placebo, on EEG evoked potentials, mood, sleep, or cognitive performance after 4 weeks of chronic administration in healthy volunteers.
Adult↗
Biological correlates of deliberate self-harm behaviour: a study of electroencephalographic, biochemical and psychological variables in parasuicide.
Clinical, electroencephalographic and biochemical variables were measured in 40 patients who attempted suicide and 27 age-matched controls. Patients had significantly higher scores for depression, hopelessness, neuroticism and psychoticism and lower scores for extraversion than controls. They also had significantly lower contingent negative variation (CNV), higher postimperative negative variation and lower whole blood serotonin values than controls. Within the patient group, vulnerability to parasuicide, as determined by previous or repeated acts of deliberate self-harm, was associated with higher scores for hopelessness and suicide intent, lower scores for extraversion and decreased CNV. Factor analysis revealed significant correlations between psychological variables and auditory evoked potential amplitudes for the vulnerable group. A profile of variables associated with increased risk of self-harm in patients presenting with attempted suicide is proposed from our data.
Adolescent↗
Absence of withdrawal effects of ritanserin following chronic dosing in healthy volunteers.
The possible development of withdrawal symptoms following abrupt discontinuation of ritanserin after chronic administration of 10 mg daily for 8 weeks was investigated in a placebo controlled trial in 40 healthy subjects. The study consisted of two phases. In the first phase, under single blind conditions, all subjects received placebo for 2 weeks followed by a single daily dose of ritanserin (10 mg) for 8 weeks. In the second phase, under double blind conditions, subjects were randomised to receive either placebo or to continue on ritanserin (10 mg) for a further 4 weeks. Psychological assessments were performed at the start of and at intervals throughout the study. Levels of anxiety, concentration, quality of sleep and morning vigilance were measured throughout by daily visual analogue scales. No significant changes were detected in any of the measures in the group of subjects who received ritanserin compared to the group who received placebo during the second phase of the study. Ritanserin discontinuation following chronic dosing in healthy volunteers does not appear to be associated with withdrawal symptoms.
Adolescent↗
Long term use of transcutaneous electrical nerve stimulation at Newcastle Pain Relief Clinic.
This retrospective study of long-term use of transcutaneous electrical nerve stimulation (TENS) at Newcastle Pain Relief Clinic indicates that TENS has been a successful analgesic treatment for 58.6% of 1582 patients attending the clinic over a period of 10 years. A wide range of pain conditions were found to respond to TENS and many patients continued to use the treatment for several years. Most patients not responding to TENS (during a home trial) returned stimulators at the first follow-up appointment. Thus TENS should be considered as a simple, safe and reusable first line treatment for many pain conditions.
Ambulatory Care Facilities↗
Analgesic effects of different pulse patterns of transcutaneous electrical nerve stimulation on cold-induced pain in normal subjects.
The analgesic efficacy of various pulse patterns of transcutaneous electrical nerve stimulation (TENS) were assessed in 84 normal healthy subjects using the cold pressor pain technique. Burst, modulation, random and continuous TENS all significantly elevated ice pain threshold. Continuous (80 Hz) TENS produced the greatest mean elevation in threshold but the response to random TENS showed the least inter-subject variation. Ice pain tolerance was increased by all modes of TENS, continuous TENS producing the greatest magnitude of response, although these changes did not reach statistical significance. Increasing the size of electrodes reduced the effect of continuous TENS. The clinical implications of these findings are discussed.
Adolescent↗
An in-depth study of long-term users of transcutaneous electrical nerve stimulation (TENS). Implications for clinical use of TENS.
This in-depth study examines the relationships between patient, stimulator and outcome variables in a large number of chronic pain patients utilising TENS on a long-term basis. 179 patients completed a TENS questionnaire designed to record age, sex, cause and site of pain and TENS treatment regime. Of these 179 patients, 107 attended our research unit for assessment of the electrical characteristics of TENS during self-administered treatment. Although a remarkable lack of correlation between patient, stimulator and outcome variables was found to exist, the analysis revealed much information of importance: 47% of patients found TENS reduced their pain by more than half; TENS analgesia was rapid both in onset (less than 0.5 h in 75% patients) and in offset (less than 0.5 h in 51% patients); one-third of patients utilised TENS for over 61 h/week; pulse frequencies between 1 and 70 Hz were utilised by 75% of patients; 44% of patients benefitted from burst mode stimulation. The clinical implications of these findings are discussed.
Adult↗
The consistency of pulse frequencies and pulse patterns of transcutaneous electrical nerve stimulation (TENS) used by chronic pain patients.
This study records the consistency of transcutaneous electrical nerve stimulation (TENS) pulse frequency and pulse pattern used by 13 chronic patients over a 1 year period. The results show that patients prefer specific pulse frequencies and pulse patterns unique to the individual and that they turn to such frequencies and patterns on subsequent treatment sessions. Pulse frequencies and pulse patterns were not related to the cause and site of pain, a finding consistent with previous study in this laboratory. This observation, coupled with the large variability in pulse frequencies and pulse patterns used between individuals, implies that patients prefer such frequencies and patterns for reasons of comfort which may not be related to mechanisms specific to the pain system.
Adult↗
The effects of auricular transcutaneous electrical nerve stimulation (TENS) on experimental pain threshold and autonomic function in healthy subjects.
The present study examines the effects of auricular transcutaneous electrical nerve stimulation (TENS) on electrical pain threshold measured at the ipsilateral wrist and autonomic functions including skin temperature, blood pressure and pulse rate in 24 healthy subjects. TENS was administered as low frequency trains of pulses delivered at a 'strong but comfortable' intensity to 1 of 3 auricular points to be examined: (i) autonomic effects (autonomic point), (ii) pain threshold effects (wrist point), and (iii) placebo effects at an unrelated point (face point). A fourth untreated group was designated as a situation control. The main finding of the study was that auricular TENS produced no significant overall effects on experimental pain threshold or autonomic functions recorded under the present conditions. However, pain threshold was found to increase by over 50% of its pretreatment baseline in 4 subjects and by 30% in 6 subjects. This rise was not dependent upon the site of auricular TENS. The possible mechanisms of such changes are discussed.
Adolescent↗
Hospital prescribing and usage of hypnotics and anxiolytics.
In-patient prescribing and usage of hypnotic and anxiolytic drugs were surveyed in a teaching hospital for 4 to 6 weeks. Twenty-one percent of admissions were prescribed these drugs which were predominantly benzodiazepines. Few patients (1.6%) were discharged with such prescriptions and subsequent usage in the community was similar to that before admission to hospital (6.1% and 6.4% respectively). In-patient consumption increased with patient age and both prescriptions and consumption were greater in women than men.
Anti-Anxiety Agents↗