Behavioral effects of caffeine, methamphetamine, and methylphenidate in the rat.
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It was possible to distinguish three closely-related psychomotor stimulants, caffeine, methamphetamine, and methylphenidate, by means of two operant behavior procedures, fixed interval and fixed number. Under the fixed interval procedure, the percentage change in the number of R(B)s per reinforcement was significantly smaller with caffeine than with methamphetamine or methylphenidate (p < .001). Under the fixed number procedure, the percentage change was significantly smaller with methamphetamine than with caffeine or methylphenidate (p < .001). Thus, methylphenidate had a methamphetamine-like effect under fixed interval and a caffeine-like effect under fixed number. (+info)
Immobility as an avoidance response, and its disruption by drugs.
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Much of the available literature on avoidance behavior is based on responses which require the animal to run, lever-press, or to make some active response to avoid noxious stimulation. The purpose of Experiment I reported in this paper was to determine whether animals can learn to sit or stand motionless in order to escape or avoid electric shock. Five experimental rats were given escape-avoidance training, while five yoked control animals received electric shocks without any response-related contingency. It was shown that an immobility avoidance response, as distinct from the unconditioned "freezing" response to shock, can be trained. The results of Experiment II (30 rats) revealed that this response is more readily acquired at higher shock intensities than at lower ones, provided escape by jumping is prevented at the high shock intensities. The effects of six doses of each of three drugs on the immobility avoidance response were studied in Experiment III (13 rats). Methylphenidate, chlorpromazine, and imipramine all produced a decrement in the immobility response, but the pattern and amount of the effects of the three drugs were quite different, one from the other. The implications of these findings for a general theory of avoidance behavior and for drug screening are discussed. (+info)
Prospective study of psychobiology in first-episode schizophrenia at Hillside Hospital.
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Heterogeneity has been a consistent problem in the research and treatment of schizophrenia. Despite marked variation in the onset, phenomenology, treatment response and outcome of schizophrenic patients, our ability to identify subtypes is remarkably limited. A major problem in schizophrenia research has been the use of cross-sectional study designs and heterogeneous patient samples at different stages of the illness and who have been previously exposed to neuroleptics which have potentially confounding effects on the disease. This study intends to identify biologic correlates of the phenomenology and course of schizophrenia by using a prospective, longitudinal, repeated measures design assessing biologic and clinical parameters including measures of psychopathology, side effects, and social adjustment to examine clinical variables of treatment response, illness course, and outcome; measures of central nervous system dopamine activity and brain morphology in patients, from the onset of their illness. Patients were ascertained at hospital admission and assessed with a battery of clinical, neuropsychologic, and biologic measures before undergoing standardized treatment for the acute and maintenance phases of the illness. Upon completion, approximately 120 first-episode patients will have entered the study and will have been followed prospectively for up to 5 years and assessed at specific time intervals. Preliminary results reveal significant abnormalities in brain morphology, growth hormone secretion, eye movement function, and psychotogenic response to dopamine agonists in first-episode, treatment-naive patients which are associated with treatment response and outcome. This article describes the study's rationale, design, and methods, and a summary of the published results to date. These are discussed in terms of their significance for putative clinical subtypes and pathophysiological models of schizophrenia. (+info)
Primary pulmonary hypertension after amfepramone (diethylpropion) with BMPR2 mutation.
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Primary pulmonary hypertension (PPH) is characterised by sustained elevations of pulmonary arterial pressure without a demonstrable cause, leading to right ventricular failure and death. Hereditary mutations in the bone morphogenetic protein receptor type II (BMPR2) gene result in familial PPH transmitted as an autosomal dominant trait, albeit with low penetrance. The causes in cases without a BMPR2 mutation are unknown, but a syndrome of pulmonary arterial hypertension (PAH) similar to hereditary PPH is associated with systemic connective tissue disease, congenital heart disease, portal hypertension, and human immunodeficiency virus infection, or with the use of appetite-suppressant drugs. The authors identified a BMPR2 gene mutation in a 27-yr-old female who developed PAH after a short course of the appetite-suppressant drug amfepramone (diethylpropion). This allowed molecular genetic counselling and prevention of potentially harmful drug exposure in the patient's son treated for attention deficit disorder with methylphenidate, an amphetamine-related drug. No BMPR2 mutation was found in four additional, unrelated patients with appetite suppressant-related PPH. The findings provide strong evidence that amfepramone can trigger primary pulmonary hypertension in a bone morphogenetic protein receptor type II gene mutation carrier, and indicate that other genes are probably implicated in genetic susceptibility to appetite suppressants. (+info)
An enzyme-linked immunosorbent assay (ELISA) for methylphenidate (Ritalin ) in urine.
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A direct enyzme-linked immunosorbent assay (ELISA) for urinary immunoreactive methylphenidate (Ritalin), in which a standard 96-well microtiter plate is used, is described. For this ELISA, a methylphenidate-thyroglobulin conjugate is immobilized to the microtiter plate and competes with methylphenidate in the standard or urine sample for antibody-binding sites. After washing, the sheep methylphenidate antibody bound to immobilized methylphenidate is detected with peroxidase-labelled goat antisheep IgG. Following a further wash, tetramethylbenzidine is added, color is developed, and the plate is read at 450 nm on an ELISA plate reader. This method is unaffected by drugs of abuse and is suitable for routine use in the toxicology laboratory. (+info)
Sequential evaluation of behavioral treatments and methylphenidate dosage for children with attention deficit hyperactivity disorder.
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We used a sequential approach to evaluate the relative and combined effects of different types of behavioral treatments, as well as dosage of methylphenidate (MPH), on the disruptive behavior of 3 students who had been diagnosed with attention deficit hyperactivity disorder. Results showed that individualized behavioral treatments produced decreases in disruptive behavior equivalent to MPH for all 3 participants and demonstrated the need to evaluate behavioral treatments and medication dosage on an individual basis. (+info)
Physician perceptions of the use of medications for attention deficit hyperactivity disorder.
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BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is a prevalent mental health condition, occurring in 3% to 5% of school-aged children. Although stimulant medications are a recommended treatment for this disorder, physicians. views of these medications have not been systematically evaluated. OBJECTIVE: This study examined physician-prescriber perceptions of using medications to treat ADHD symptoms in children or adolescents. METHODS: A survey was developed with 4 physicians expert in treating ADHD in children. The survey was pilot-tested with a sample of 10 practicing physicians. A sample of 1,000 physicians, with a history of prescribing stimulant medications to children or adolescents, was randomly selected and mailed a 30-item survey. Items were rated on a 7-point response scale (strongly agree, agree, slightly agree, undecided, slightly disagree, disagree, strongly disagree). RESULTS: A total of 365 physicians responded to the survey, for a 37% response rate. More than 92% of respondents strongly agreed or agreed that ADHD symptoms cause problems in pediatric patients and stimulants are effective in treating ADHD. The stimulant drug side effects of decreased appetite or weight loss, sleep disruption, and exacerbation of anxiety were a concern (strongly agree or agree response) for 32%, 50%, and 22% of physicians, respectively. Diversion of ADHD medication was a concern for 19% of respondents. Physicians reported that controlled medications for children or adolescents with ADHD are a burden for themselves (32% strongly agreed or agreed), for their staff (37% strongly agreed or agreed), and for parents (40% strongly agreed or agreed). Approximately 38% of physicians responded that they would prefer prescribing a nonstimulant medication with a U.S. Food and Drug Administration indication for treating children or adolescents instead of a stimulant medication, and 58% would prefer prescribing a noncontrolled medication that does not have evidence of abuse potential versus one that is controlled and has evidence of abuse potential. CONCLUSION: Although physicians overwhelmingly perceive stimulant medications as being effective for treating ADHD symptoms in children or adolescents, many would prefer a nonstimulant medication. While many physicians consider the side effects of the stimulants easily managed, others are concerned about prescribing stimulants because of their side effects, risk of diversion, and administrative burden. The majority of physicians would prefer to prescribe a noncontrolled medication without abuse potential instead of a controlled medication to treat children or adolescents with ADHD. (+info)
Attention patterns in children with attention deficit disorder with or without hyperactivity.
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The objective of this study was to differentiate the attention patterns associated with attention deficit disorder with or without hyperactivity using continuous performance test (CPT). The diagnoses were based on the DSM-III, III-R, and IV criteria and of the 39 children who participated in the study, 14 had attention deficit disorder with hyperactivity (ADDH) and 11 had attention deficit disorder without hyperactivity (ADDWO), while 14 normal children served as a control group. Attention patterns were examined according to the performance of subjects on the CPT and parental scores on the ADHD Rating Scale, the Child Attention Profile, and the Conners Rating Scale. CPT performances were assessed before and after administration of 10 mg methylphenidate. We found as hypothesized that the CPT differentiated between the ADDH and ADDWO groups. However, contrary to our expectations, the ADDH children made more omission errors than the ADDWO children; they also showed more hyperactivity and impulsivity. The performance of both groups improved to an equal degree after the administration of methylphenidate. It is concluded that different subtypes of the attention deficit disorders are characterized by different attention profiles and that methylphenidate improves scores on test of continuous performance. (+info)