Urbanisation and Declining Suicide Rates in China Between 2005 and 2017

BACKGROUND

Worldwide suicide rates have declined since 2000s, with China being the primary contributor. This study aimed to investigate whether urbanisation is associated with decreasing suicide rates in China.

METHODS

Suicide rates and economic indicators of 31 provinces, municipalities, and autonomous regions of China between 2005 and 2017 were analysed. Poisson random intercept models were used to determine associations between suicide rates, urbanicity, sexes, and gross regional product (GRP).

RESULTS

Between 2005 and 2017, suicide rates in 31 provinces, municipalities, and autonomous regions of China continued to decrease. Urbanicity and GRP were associated with decreased suicide rates among Chinese males and females. An increase in urbanicity by 1% was associated with a 2.2% decrease in suicide rates (p < 0.001). The most urbanised and populous cities (Beijing, Shanghai, Tianjin) had the lowest suicide rates. Urbanicity was associated with a greater decline in suicide rates among females, compared with males. Association between increased urbanicity and reduced suicide rates was independent of GRP.

CONCLUSION

Urbanisation was associated with declining suicide rates in China; this association was stronger among females than males.

Non-Psychosis Symptoms of Clozapine Withdrawal: a Systematic Review

OBJECTIVE

Clozapine is a potent antipsychotic medication with a complex receptor profile. It is reserved for treatment-resistant schizophrenia. We systematically reviewed studies of non-psychosis symptoms of clozapine withdrawal.

METHODS

CINAHL, Medline, PsycINFO, PubMed, and the Cochrane Database of Systematic Reviews were searched using the keywords 'clozapine,' and 'withdrawal,' or 'supersensitivity,' 'cessation,' 'rebound,' or 'discontinuation'. Studies related to non-psychosis symptoms after clozapine withdrawal were included.

RESULTS

Five original studies and 63 case reports / series were included in analysis. In 195 patients included in the five original studies, approximately 20% experienced non-psychosis symptoms following discontinuation of clozapine. In 89 patients in four of the studies, 27 experienced cholinergic rebound, 13 exhibited extrapyramidal symptoms (including tardive dyskinesia), and three had catatonia. In 63 case reports / series included, 72 patients with non-psychosis symptoms were reported, which were catatonia (n=30), dystonia or dyskinesia (n=17), cholinergic rebound (n=11), serotonin syndrome (n=4), mania (n=3), insomnia (n=3), neuroleptic malignant syndrome (NMS) [n=3, one of them had both catatonia and NMS], and de novo obsessive compulsive symptoms (n=2). Restarting clozapine appeared to be the most effective treatment.

CONCLUSIONS

Non-psychosis symptoms following clozapine withdrawal have important clinical implications. Clinicians should be aware of the possible presentations of symptoms to ensure early recognition and management. Further research is warranted to better characterise the prevalence, risk factors, prognosis, and optimal drug dosing for each withdrawal symptom.

Psychosis Related to Baclofen Withdrawal or Overdose: A Systematic Review

OBJECTIVE

To systematically review case reports of psychosis related to withdrawal or overdose of baclofen, which is a gamma-aminobutyric acid (GABA) _B agonist.

METHODS

PubMed, MEDLINE, CINAHL, and PsychINFO were searched to identify articles related to psychosis secondary to withdrawal or overdose of baclofen using the terms 'baclofen' and ' psychosis'. Comparisons were made between cases in terms of concomitant antipsychotic use, diagnosis of delirium, and evidence of association. Quality of case reports was assessed using the CARE Case Report Guidelines checklist.

RESULTS

In total, 34 patients from 28 case reports were reviewed. Twenty-three patients experienced psychosis upon baclofen withdrawal; among them, 18 had resolution of psychosis upon reinitiation of baclofen, whereas antipsychotic monotherapy was less successful (only four of eight patients responded). An additional baclofen withdrawal period led to recurrence of psychotic symptoms in four of seven patients. Eleven patients had psychosis on induction or after overdose of baclofen; among them, four patients had resolution of psychosis upon cessation of baclofen. The mean quality of the case reports was 6.4 of 13.

CONCLUSION

Considering its GABAergic agonism, along with evidence of psychosis on induction or withdrawal, baclofen may have some antipsychotic and pro-psychotic properties.

Deeply Virtual Compton Scattering Cross Section at High Bjorken x_{B}

We report high-precision measurements of the deeply virtual Compton scattering (DVCS) cross section at high values of the Bjorken variable x_{B}. DVCS is sensitive to the generalized parton distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton form factors (CFFs) of the nucleon as a function of x_{B}, while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs.

Deep Exclusive Electroproduction of π^{0} at High Q^{2} in the Quark Valence Regime

We report measurements of the exclusive neutral pion electroproduction cross section off protons at large values of x_{B} (0.36, 0.48, and 0.60) and Q^{2} (3.1 to 8.4  GeV^{2}) obtained from Jefferson Lab Hall A experiment E12-06-014. The corresponding structure functions dσ_{T}/dt+εdσ_{L}/dt, dσ_{TT}/dt, dσ_{LT}/dt, and dσ_{LT^{'}}/dt are extracted as a function of the proton momentum transfer t-t_{min}. The results suggest the amplitude for transversely polarized virtual photons continues to dominate the cross section throughout this kinematic range. The data are well described by calculations based on transversity generalized parton distributions coupled to a helicity flip distribution amplitude of the pion, thus providing a unique way to probe the structure of the nucleon.

When should governments increase the supply of psychiatric beds?

Low numbers of hospital-based psychiatric beds create problems for people with severe mental illness (SMI), when they face extended emergency department (ED) waits, higher thresholds for admission to an acute bed, and short revolving-door stays with high rates of rehospitalisation. Limited access to inpatient treatment has been associated with higher suicide risk, premature mortality, homelessness, violent crime and incarceration. Ultimately, people with SMI can be transinstitutionalised to the criminal justice system. In the USA, for example, prisons have replaced mental hospitals as the largest institutions housing people with SMI. There is no international consensus on the safe minimum numbers of acute, forensic and rehabilitation beds needed to reduce these risks. As a consequence, Organisation for Economic Cooperation and Development (OECD) countries have wide variations in the mix of hospital beds with an average of 71 beds per 100 000 population. Policymakers face difficult choices with few studies to guide decisions on supplying beds. The UK Royal College of Psychiatrists offered a policy framework, which was adapted for Australia. The government of the State of South Australia increased the supplies of crisis, acute and forensic beds to meet a mandatory target to safely reduce mental health boarding in the EDs.

Structure and hydrogen bonding in neat N-methylacetamide: classical molecular dynamics and Raman spectroscopy studies of a liquid of peptidic fragments

The results of classical molecular dynamics (MD) simulations and Raman spectroscopy studies of neat liquid N-methylacetamide (NMA), the simplest model system relevant to the peptides, are reported as a function of temperature and pressure. The MD simulations predict that near ambient conditions, the molecules form a hydrogen bond network consisting primarily of linear chains. Both the links between molecules within the hydrogen-bonded chains and the associations between chains are stabilized by weak methyl-donated "improper" hydrogen bonds. The three-dimensional structural motifs observed in the liquid show some similarity to protein beta-sheets. The temperature and pressure dependence of the hydrogen bond network, as probed by the mode frequency of the experimentally determined amide-I Raman band, blue shifts on heating and red shifts under compression, respectively, suggesting weakened and enhanced hydrogen bonding in response to temperature and pressure increases. Disruption of the hydrogen-bonding network is clearly observed in the simulation data as temperature is increased, whereas the improper hydrogen bonding is enhanced under compression to reduce the energetic cost of increasing the packing fraction. Because of the neglect of polarizability in the molecular model, the computed dielectric constant is underestimated compared to the experimental value, indicating that the simulation may underestimate dipolar coupling in the liquid.

The length dependence of translational diffusion, free solution electrophoretic mobility, and electrophoretic tether force of rigid rod-like model duplex DNA

In this work, boundary element modeling is used to study the transport of highly charged rod-like model polyions of various length under a variety of different aqueous salt conditions. Transport properties considered include free solution electrophoretic mobility, translational diffusion, and the components of the "tether force" tensor. The model parameters are chosen to coincide with transport measurements of duplex DNA carried out under six different salt/temperature conditions. The focus of the analysis is on the length dependence of the free solution electrophoretic mobility. In a solution containing 0.04 M Tris-acetate buffer at 25 degrees C, calculated mobilities using straight rod models show a stronger dependence on fragment length than that observed experimentally. By carrying out model studies on curved rod models, it is concluded that the "leveling off" of mobility with fragment length is due, in part at least, to the finite curvature of DNA. Experimental mobilities of long duplex DNA in monovalent alkali salts are reasonably well explained once account is taken of long-range bending and the simplifying assumptions of the model studies.

Commercially available folic acid supplements and their compliance with the British Pharmacopoeia test for dissolution

A recent report suggested that some folic acid preparations available in the United States failed to meet the specifications for dissolution specified by the US Pharmacopoeia (USP), of 70 per cent drug release in the first hour of testing. The Teratology Society recommends that women of childbearing age should take a daily supplement of 400 microg folic acid when they are trying to conceive, to reduce the risk of foetal neural tube defects. The consequence of this failure to meet the USP requirements may be that an inadequate dose of folate may be absorbed and thus the expected level of protection against neural tube defects not afforded. The purpose of the present study was to examine a number of brands of folic acid (400 microg), available commercially in the United Kingdom, for compliance with the British Pharmacopoeia (BP) test for dissolution. Ten tablets (or capsules) from each of 11 brands were tested using dissolution apparatus compliant with BP requirements, using 0.1 M sodium hydroxide as the dissolution medium. The results indicated that four of the brands failed to release 70 per cent of the nominal drug content in the first hour of test and thus did not comply with the test. Two of the seven brands that passed the test went on to release more than 150 per cent of the nominal 400 microg drug content. These results highlight the problems of dose uniformity and the potential health risks of slow dissolution and under-dosing in commercially available folic acid dosage forms.

Gender differences in the relationship between depression and suicidal ideation in young adolescents

OBJECTIVE

This study examined the risk relationship between depressive symptomatology and suicidal ideation for young adolescent males and females.

METHOD

A large cohort of students in their first year of high school completed the Center for Epidemiological Studies Depression Scale (CES-D) and the Adolescent Suicide Questionnaire. The risk relationship between depressive symptomatology and suicidal ideation was modelled using non-parametric kernel-smoothing techniques.

RESULTS

Suicidal ideation was more frequently reported by females compared with males which was partly explained by females having higher mean depression scores. At moderate levels of depression females also had a significantly higher risk of suicidal ideation compared with males and this increased risk contributed to the overall higher levels of female ideation.

CONCLUSIONS

The risk relationship between depressive symptomatology and suicidal ideation is different for young adolescent males and females. The results indicate that moderate levels of depressive symptomatology can be associated with suicidal ideation (especially among young females) and that for these young people a suicide risk assessment is required.

Effects of spatial and nonspatial cognitive activity on postural stability

Is postural stability controlled automatically, or is it affected by concurrent cognitive activity? Are the effects influenced by the nature of the cognitive activity required, and do they increase in old age? To address these questions, 70 participants aged 20-79 years were asked to stand as still as possible on a force platform (postural control task) while performing (a) no cognitive task, (b) a spatial memory task, and (c) a nonspatial memory task. The memory tasks were also performed while seated as a comparison condition. Both spatial and nonspatial memory recall declined with increasing age but were unaffected by position (standing vs. seated). Postural stability declined with age; moreover, there was support for an earlier finding that age decline was greatest when performing the spatial memory task. Each recording period was split into two phases which, for the spatial and nonspatial memory tasks, corresponded to encoding and maintaining the stimuli. In comparison with no task, participants were more stable when encoding stimuli (particularly in the spatial task), but they were less stable when maintaining stimuli (particularly in the nonspatial task). The results suggest that postural stability can be affected by cognitive activity in complex ways, depending on the age of participants, the type of cognitive task (spatial vs. nonspatial), and the cognitive processing required (encoding vs. maintenance).

Use of webboards for distance learning: a physical therapy model

In today's world of ever-increasing knowledge and technology, mastering the use of information is critical for success. U.S. Army physical therapists have successfully used the Knowledge Management Network as a tool to foster communication, education, and training. The model outlined in this article can serve both as a model for promoting distance learning and as a success story of how to merge today's technology with the medical community to improve productivity and communication.

Intestinal stomas in Crohn's disease

Stomal construction is as important as the establishment of hemostasis. Appropriate preoperative assessment and adherence to accepted construction techniques usually will avoid stomal complications. In patients who suffer adverse consequences, accurate assessment and appropriate management principles are essential to properly address the problem.

Brief therapy for children's mental health problems: outcomes in a rural setting

In rural areas where specialist services are not readily accessible, there are practical advantages to providing short courses of therapy for children's mental health problems. Fifty-five parents from a rural area in South Australia completed questionnaires before and 3 months after receiving brief, family-oriented therapy from a child and adolescent mental health service. Clinically, these families were assessed as being suitable for brief therapy because the children had moderately severe emotional and behavioural problems and the families were not severely dysfunctional. The screening process sought to exclude more serious and complex presentations so those families were not included in the current study. Questionnaires measuring the severity of children's mental health problems (Child Behavior Checklist) and the degree of family dysfunction (Family Assessment Device general functioning subscale) suggested that, on average, the sample met these entry criteria. The follow-up evaluation after brief therapy found significant overall improvement in the Child Behavior Checklist scores, however some children continued to show substantial difficulties. Parents' satisfaction with therapy was related to these scores after treatment. The results suggest that brief therapy was appropriate for most of the families and that routine follow-up could help determine those who might benefit from further assistance.

Relationship of cardiac inpatients' outcomes to mood state

This descriptive study used a computerized charge capture system (CCCS) to explore the differences of cost and length of stay (LOS) between cardiac inpatients with a diagnosis of depression (n = 144) and cardiac inpatients without depression (n = 9,099). Level of severity, gender, and mood state (depression vs. nondepression) were also compared. A matched sample of 352 nondepressed patients was compared with a sample of 94 depressed patients. There were no significant differences between the depressed and nondepressed groups. However, the study did indicate interesting findings regarding mood state, gender, and cardiac outcomes. Depression was significantly overrepresented among females (chi 2 = 24.0, df = 1, P < 0.05). When gender and mood state were considered together, women with cardiac disease who were depressed had significantly longer lengths of stay (LOSs) and increased costs than men with depression (F = 6.6, df = 1, P = 0.01). A major unanticipated finding was the extremely low incidence of depression detected in these patients (1.6%) when compared with patients in other studies. One possible reason for the low incidence of depression was related to the use of a financial, rather than a clinical, data set.

Undernutrition and function: another piece in the jigsaw [commet]

The stomach, small intestine and pancreas share in the progressive bodily dysfunction associated with undernutrition and weight loss. All these changes are reversed by nutritional support whether given enterally or parenterally, emphasizing that parenteral and enteral nutrition are the treatment of gastrointestinal failure as dialysis is of renal failure or ventilation is of respiratory failure. The observations described by Winter and colleagues have important implications for our understanding of the relationship between nutrition and physiology. They also have important implications for the care of patients with gastrointestinal disease.

Prediction of 10 repetition maximum for short-arc quadriceps exercise from hand-held dynamometer and anthropometric measurements

Short-arc quadriceps exercise are commonly prescribed in physical therapy for strengthening knee extensor musculature. Determining the appropriate starting resistance has traditionally been a trial-and-error procedure. Therefore, developing an expedient method of estimating the correct starting resistance may lead to a more accurate exercise prescription. The primary purpose of this study was to establish a technique for predicting an individual's 10 repetition maximum (10 RM) based on hand-held dynamometer (HHD) strength recording and additional anthropometric predictor variables. Fifty healthy subjects (31 males and 19 females), aged 22-53 years, participated in the study. A prediction equation for determining 10 RM using HHD strength recording, weight, gender, and age was developed. By implementing this equation, clinicians can predict a normal, healthy, young to middle-aged adult's 10 RM within +/- 4.17 kg with a 95% confidence level (SEE = 2.13 kg).

Continuing medical education in marital and family therapy: a survey of South Australian psychiatrists

OBJECTIVE

South Australian psychiatrists were surveyed to determine their impressions of the usefulness of marital and family therapy (MFT) in the management of serious psychiatric conditions and to ascertain their previous experience with Continuing Medical Education (CME) about family therapy. It was expected that psychiatrists' preferences regarding CME would be related to their clinical experience of the usefulness of MFT.

METHOD

One hundred and twenty psychiatrists returned a questionnaire about their training, clinical and research interests, with ratings of the usefulness of MFT and CME preferences. This represented 65% of those eligible for the CME programme.

RESULTS

Thirteen percent of the respondents found MFT to be extremely useful and a further 47% found it moderately useful in their current practice. There was evidence of a possible training effect: respondents who had previous CME rated MFT as more useful, especially for mood disorders. Furthermore, the treatment of mood disorders seemed to have a particular relevance in family psychiatry, making a statistically unique contribution to ratings of MFT usefulness in the respondents' total practice. Sixty-nine percent of the respondents requested further CME in family therapy. This represented 45% of all South Australian psychiatrists. Respondents who rated MFT as more useful in practice were significantly more likely to be interested in CME.

CONCLUSIONS

There seems to be sufficient interest and clinical experience among psychiatrists for MFT to be included in CME courses. It is recommended that further training focus on major mental disorders, especially mood disorders and schizophrenia.

Adolescent suicide, depression and family dysfunction

This study investigated associations between adolescents' perceptions of their family dynamics (McMaster Family Assessment Device, FAD) and depression, suicide thoughts and attempts. High school students (mean age 15.2 years) completed self-report questionnaires including the Beck Depression Inventory (BDI), the FAD, questions about suicidal thoughts, plans and attempts, deliberate self harm, and selected life experiences. Univariate analysis showed that family dysfunction measured on the FAD is associated with thinking and planning suicide, deliberate self harm, suicide attempts, as well as severe depression (BDI > or = 22). Despite this, stepwise regression indicated that family dysfunction influences suicide behaviors indirectly through other variables such as depression. The FAD is recommended as a useful addition to questionnaires seeking to identify vulnerability to both depression and adolescent attempted suicide in early detection studies.

Effects of surface texture on weight perception when lifting objects with a precision grip

In this paper, we show that, when lifting an object using a precision grip with the distal pads of the thumb and index finger at its sides, the perceived weight depends on the object's surface texture. The smoother the surface texture, the greater the perceived weight. We suggest that a smoother object is judged to be heavier because the grip force, normal to the surface, required to prevent it from slipping is greater. The possibility of there being an influence of surface texture per se is excluded by a second experiment that employed a variant of the precision grip in which the thumb supports the weight of the object from underneath. With the grip oriented in this way, there is no need to match grip force to surface texture and, under these conditions, there is no effect of surface texture on weight perception. In the first two experiments, the test and comparison weights were lifted successively by the same hand. In a third experiment, the effect of surface texture was replicated for sequential lifts made with separate hands. Thus, the effect is not restricted to comparisons made with the same hand.

Evaluation of a patient information booklet

Preoperative teaching is an integral component of the care surgical patients receive. The need for consistent preoperative information has resulted in growing use of printed health information. There are many printed materials for nurses to choose from; however, these materials serve no useful teaching purpose if patients are unable to understand them. This study evaluates how well surgical patients understand the content presented in an educational booklet used for preoperative teaching. A Cloze test was designed to assess comprehension of a booklet prepared at a grade five reading level. Scores revealed that 84% of subjects scored above 56% and were able to comprehend the material independently; 10% scored between 44% and 56%, indicating they would require some help; and 6% scored less than 44% and were not able to comprehend the information.

Influences on control in diabetes mellitus: patient, doctor, practice, or delivery of care?

OBJECTIVE

To assess patient, doctor, practice, and process of care variables for their effect on glycaemic control in diabetes mellitus, and to quantify their relative effects.

DESIGN

Search of general practice medical records, patient questionnaires and examination, doctor questionnaire, videotaping and analysis of consultations, and practice questionnaire.

SETTING

12 practices with 32 participating general practitioners in Nottinghamshire.

SUBJECTS

318 patients randomly selected from those with diabetes in each practice, 10 for each participating doctor.

MAIN OUTCOME MEASURE

Glycaemic control as measured by random glycated haemoglobin A1c estimation (random haemoglobin A1 measurement).

RESULTS

Glycaemic control was significantly related to the disease process as measured by years since diagnosis, treatment group, and number of diabetes related clinical events. Females had significantly worse control than males. Other patient factors, such as age, social class, lifestyle, attitudes, satisfaction, and knowledge, had no association with glycaemic control. Of all the doctor factors examined, only doctors who professed a special interest in diabetes achieved significantly better glycaemic control. Bigger and better equipped practices and those with a diabetic miniclinic had patients with significantly better glycaemic control, as did those with access to dietetic advice. Patients attending hospital clinics had worse glycaemic control, but this seemed to be attributable to the case mix and practice characteristics. Shared care did not contribute to the multiple linear regression model.

CONCLUSION

Glycaemic control among diabetic patients in the community is related to such factors as treatment group, sex, and years since diagnosis; it is also related to the organisation and process of care. The findings support concentrating diabetic care on partners with special interests in diabetes in well equipped practices with adequate dietetic support.

The pre-admission program: a proactive approach to management

Spiralling health care costs are forcing hospital administrators to find creative alternatives to traditional health care delivery systems. One of the most recent innovations rapidly gaining favour is the pre-admission program. The article describes how a well-developed pre-admission program can have a significantly positive impact on bed utilization, diagnostic services, patient satisfaction and overall quality of care, and provides examples from a successful pre-admission program implemented at the University of Alberta Hospitals.

Bovine dopamine beta-hydroxylase cDNA. Complete coding sequence and expression in mammalian cells with vaccinia virus vector

We have isolated cDNA clones for bovine dopamine beta-hydroxylase from an adrenal medulla cDNA library and have determined the complete coding sequence. The largest cDNA clone isolated from the library is 2.4 kilobase pairs (kb) and contains an open reading frame of 1788 bases, coding for a protein of 597 amino acids and Mr = 66,803. The predicted amino acid sequence of the bovine cDNA contains 85% identity with human dopamine beta-hydroxylase (Lamouroux, A., Vingny, A., Faucon Biquet, N., Darmon, M. C., Franck, R., Henry, J.P., and Mallet, J. (1987) EMBO J. 6, 3931-3937; Kobayashi, K., Kurosawa, Y., Fujita, K., and Nagatsu, T. (1989) Nucleic Acids Res. 17, 1089-1102). Northern blot analysis reveals that the cDNA hybridizes to an mRNA of 2.4 kb present in bovine adrenal medulla, but not in kidney, heart, or liver. In addition, the cDNA hybridizes to a second RNA species of 5.5 kb, which is 4-fold less abundant than the 2.4-kb RNA. In vitro translation of a synthetic RNA transcribed from the 2.4-kb cDNA produces a 68-kDa protein, which is specifically immunoprecipitated by antiserum to bovine dopamine beta-hydroxylase. The 2.4-kb cDNA was cloned into a vaccinia virus vector, and the recombinant virus was used to infect the rat pheochromocytoma PC12 and monkey BSC-40 fibroblast cell lines. In both cell lines, infection with recombinant virus produces a protein of Mr = 75,000, which reacts with antiserum to bovine dopamine beta-hydroxylase. These results indicate that the 2.4-kb cDNA contains the genetic information necessary to code for the bovine dopamine beta-hydroxylase subunit.

The detection of sleep onset: behavioral, physiological, and subjective convergence

In this report, a sleep deprivation/multiple arousal paradigm was used in which response time (RT) and respiratory and electroencephalographic (EEG) measures were combined with a continuous behavioral index of arousal (a deadman switch) and frequently repeated Stanford Sleepiness Scale ratings to examine the process of falling asleep. Sleep was defined behaviorally as failure to respond to the faint auditory RT cue. Although response rates decreased significantly as EEG stages passed from W through 1 to 2, responding continued in both light "sleep" stages. Respiratory, subjective, and DM changes were more pronounced between Stages W and 1 than between Stages 1 and 2. If the criterion for wakefulness is cognitive response to external stimulation, accurate distinctions between sleep and wakefulness can only be made in EEG Stages 3, 4, and rapid eye movement sleep. If EEG is the criterion, then the data suggest that cognitive response is possible during Stages 1 and 2 "sleep". The concept of a Sleep Onset Period, characterized by lengthening response times and intermittent response failure (thereby reflecting neither true sleep nor wakefulness), may provide a useful resolution to this definitional dilemma.

Age and simple reaction time: decade differences for 5,325 subjects

In a booth at a public exhibition entitled "Medicines for Man," 5,325 men, women, and children carried out a 1-minute test of simple reaction time (RT) with 1 to 10 second randomized variable preparatory interval (PI). They recorded their ages by decade. Average RT over the last eight (of ten) trials increased progressively from the 20s up to age 60 and over, and downward to the teens and under 10s. The single fastest RT in each test varied much less with age, only the 20s being clearly faster than the rest, with the under 10s slower. Within-subject variability of RT was increased only in the under 10s and over 60s. Ability to sustain attention during the longer PIs may underlie the gross average RT differences with age, and possibly some more basic neural property the superiority of the 20s in fastest RT.

Plasma concentrations and clinical effects after single oral doses of prazepam, clorazepate, and diazepam

In a double-blind parallel-group pharmacokinetic and pharmacodynamic study, 31 healthy volunteers received single oral doses of prazepam (10 mg), clorazepate (7.5 mg), or diazepam (5 mg). Appearance in plasma of diazepam and of desmethyldiazepam was rapid after administration of diazepam and clorazepate, respectively, with peak plasma concentrations reached within an average of 1 hour. After oral prazepam, however, desmethyldiazepam appeared in blood slowly, with the highest mean concentration at 6 hours postdosage. Clinical self-ratings of fatigue and of "feeling spacey" were significantly different among groups, with changes over baseline being more marked with clorazepate and diazepam than with prazepam. Thus, differences in absorption rate of orally administered benzodiazepines can lead to differences in the intensity of single-dose effects, despite administration of doses that are equivalent in terms of long-term anxiolytic efficacy.