TOWARD A METHODOLOGY OF WITHDRAWAL DESIGNS FOR THE ASSESSMENT OF RESPONSE MAINTENANCE

Single-case experimental designs have advanced considerably in the evaluation of functional relationships between interventions and behavior change. The systematic investigation of response maintenance once intervention effects have been demonstrated has, however, received relatively little attention. The lack of research on maintenance may stem in part from the paucity of design options that systematically evaluate factors that contribute to maintenance. The present paper discusses three design options potentially useful for the investigation of response maintenance. These include: (a) the sequential-withdrawal, (b) the partial-withdrawal, and (c) the partial-sequential withdrawal designs. Each design is illustrated and potential limitations are discussed.     

Effects of income on drug choice in humans.

The effects of income (money available to spend during the experimental session) on human choice were examined in a concurrent-schedule arrangement. Subjects were 7 nicotine-dependent smokers, and reinforcers were puffs on the subject's usual brand of cigarette ("own") and puffs on a less preferred brand of cigarette with equal nicotine content ("other"). Across sessions, income varied and the price of the two reinforcers was held constant, with the other puffs one fifth the price of the own puffs. As income increased, consumption of own puffs increased while consumption of the less expensive other puffs decreased. These effects of income on choice were highly consistent across subjects. For some subjects, however, income had little effect on total puff consumption. Finally, an additional condition examined whether price and income manipulations would have functionally equivalent effects on choice by repeating an income condition in which the price of the other brand was increased. Although the increased price of the other puffs decreased their consumption in 4 subjects, 2 subjects showed increased consumption of the other puffs at the higher price. The results, when defined in economic terms, indicate that the own puffs were a normal good (consumption and income are directly related), the other puffs were an inferior good (consumption and income are inversely related), and the direct relationship between consumption of the other puffs and their price is defined as a Giffengood effect. The latter result also suggests that for these 2 subjects, price and income manipulations had equivalent effects on choice. These results extend findings from previous studies that have examined the effects of income on choice responding to human subjects and drug reinforcers, and provide a framework for further experimental tests of the effects of income on human choice behavior. Methodological and theoretical implications for the study of choice and for behavioral pharmacology are discussed.     

Aversive and compensatory classical conditioning with diazepam as conditional stimulus

The purpose of the first experiment was to investigate whether diazepam could acquire anxiogenic properties by signalling an aversive event. Rats were trained in an operant chamber in the pentylenetetrazol (PTZ) model of anxiety. Thereafter the animals were divided into groups that received classical diazepam conditioning (Group 1), and conditioning of diazepam + tone (Group 2). In the test phase diazepam was injected prior to placement in the operant chamber. Group 2 selected the PTZ-appropriate lever more often than the other groups, indicating that the tone induced anxiety, and diazepam did not. Tones and shock may therefore be more easily associated than diazepam and shock. The second experiment investigated this. Rats were trained the same way as in the first experiment. Thereafter the experimental group received injections of a small dose of diazepam prior to a second injection of a large dose of diazepam. The hypothesis was that a compensatory anxiogenic conditional response to diazepam's anxiolytic effect should be elicited by the small dose. There were no differences between the groups in lever selection, indicating that a compensatory anxiogenic response was not elicited.     

医生主动放弃治疗的法律问题

医生对身患绝症,没有治疗效果的病人主动放弃治疗给法律带来了三方面的冲击。法律在放弃治疗问题上的革命否定了对该类病人的“治疗”是真正意义上的治疗,否定了延长此类病人的存活期限一定符合病人利益的主张,甚至否定了此类病人的生命权益。在我国有关放弃治疗立法中,应注意对放弃治疗的定义、对象、决定的作出者以及放弃治疗的例外作出界定,设立放弃治疗宣查委员会,在法律上规定其职能,。     

Helping behaviour among people who use drugs: Altruism and mutual aid in a harm reduction program

People who use drugs, and particularly people experiencing addiction, are rarely afforded the opportunity to have their voices heard when it comes to drug treatment or drug policy or even when attempting to define themselves and their life experiences. Of course, there is much more to a person than one area of their behaviour. The current study seeks to capture and understand the lived experiences of people who use drugs, with a focus on their relationships and helping behaviour. We interviewed 32 participants in a harm reduction program seeking to provide understanding beyond stigmatizing and criminalizing drug narratives, by exploring their motivation and context for helping behaviours. Grounded theory methodology was used to understand the patterns of helping behaviour, along with the contexts in which help is or is not given. We particularly focus on participants' distribution of syringes and carrying medicine to reverse overdose (naloxone). Participants shared stories of altruism and mutual aid, along with barriers and disincentives to helping others. We situate these behaviours within contrasting environments of a free harm reduction program and the competitive market system of the U.S. society. Implications for practice and public policy are discussed.     

Validation of continuous measures of peer social interaction with self- and teacher-reports of friendship and social engagement

ABSTRACT

The present study validates a new procedure that combines continuous measures of proximity (Ubisense) and vocalization (LENA) into measures of peer social interaction. The data were collected from 4 boys and 5 girls (ages 2–3 at the outset) on 8 separate days (3–4 hours per day) over the course of an academic year. Teacher reports of friendship were positively correlated with continuous measures of dyadic social interaction (i.e., the amount of time two children spent in proximity to one another, talking). Self-reports of reciprocated friendship were marginally correlated with continuous measures of dyadic social interaction, but only in the spring semester (when children were older and their reports of friendship more reliable). At the individual level, peer nominations of likeability, and teacher ratings of sociability and withdrawal were correlated with continuous measures of social interaction (i.e., the amount of time a child spent in proximity to other children, talking).     

Adolescent gambling and drug use

In this study, 4516 adolescents (aged 11–16 years) completed a questionnaire examining the relationship between underage National Lottery gambling, underage scratchcard gambling, cigarette smoking, drinking alcohol and drug use. It was found that these behaviours were closely linked. Adolescent gamblers reported that they were significantly more likely to drink alcohol (particularly ‘alcopops’), smoke tobacco and take drugs compared to non-gamblers. © 1998 John Wiley & Sons, Ltd.     

Assessing unit-price related remifentanil choice in rhesus monkeys

Given a commodity available at different prices, a unit-price account of choice predicts preference for the cheaper alternative. This experiment determined if rhesus monkeys preferred remifentanil (an ultra-short-acting micro-opioid agonist) delivered at a lower unit price over a higher-priced remifentanil alternative (Phases 1 and 3). Choice between equal-priced alternatives also was assessed (Phase 2). A discrete-trials procedure was arranged in which three monkeys chose between two remifentanil alternatives by responding on one of two levers. Different prices were arranged by manipulating drug dose (0.3 and 0.1 microg/kg/injection) and/or the ratio requirement. Monkeys usually chose the larger-dose alternative even when it was more expensive. Only when unit prices were relatively high (e.g., large response requirements) did monkeys choose the cheaper (or equally priced) smaller-dose alternative. Employing larger doses (0.9 and 0.3 microg/kg/injection) attenuated the larger-dose preference. The results demonstrate that choice was not determined simply by unit price. An alternative model that employs demand-function analysis to generate choice predictions is proposed.     

Traversing boundaries: clinical ethics,moral experience,and the withdrawal of life supports

While many have suggested that to withdraw medical interventions is ethically equivalent to withholding them, the moral complexity of actually withdrawing life supportive interventions from a patient cannot be ignored. Utilizing interplay between expository and narrative styles, and drawing upon our experiences with patients, families, nurses, and physicians when life supports have been withdrawn, we explore the changeable character of boundaries in end-of-life situations. We consider ways in which boundaries imply differences – for example, between cognition and performance – and how the encounter with boundaries can generate altered meanings important for understanding decisions and actions in these contexts. We conclude that the reliance on mere roles to support the moral weight of withdrawing medical interventions is inadequate. Roles that lead us to such moments are exceeded by the responsibility encountered in such moments. And here, we suggest, is the momentous character of withdrawal: it presents the grave astonishment, the trembling awe, in the not-being-there of the other in death.     

Navigation in the Morris swim task as a baseline for drug discrimination: a demonstration with morphine

A morphine versus saline discrimination was demonstrated using the Morris swim task as the behavioral baseline. The apparatus was a large circular pool filled with water made opaque by floating polypropylene pellets. Rats were placed in the tank in randomly selected locations (12 trials per session) and could escape by swimming to a platform submerged 2 cm below the surface. Morphine (5.6 mg/kg) or saline was injected prior to training sessions. The position of the platform in a given session depended on the drug condition, thus forming the basis for discriminative responding. Three of the 4 rats acquired the discrimination, as evidenced by direct swims to the condition-appropriate platform. Generalization probe sessions were conducted following acquisition. Probe sessions were preceded by injections of morphine (0, 1.0, 3.0, 5.6, or 10.0 mg/kg) and involved placing the rat in the pool for 1 min without a platform. Swim patterns revealed a gradient, with probe swimming more concentrated in the area of the morphine platform position after higher morphine doses. In addition, dose-dependent increases in the likelihood of swimming first to the morphine-associated platform location were obtained. These results illustrate the generality of drug discrimination across different behavioral procedures, and of particular interest with respect to spatial learning, demonstrate interoceptive stimulus control of navigation.