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Biomedical subjects

R R Griffiths

Publications and source records attributed to R R Griffiths.

At least 199 records · Page 11Linked to original sources
PubMed1980

Double-blind evaluation of reinforcing and anorectic actions of weight control medications. Interaction of pharmacological and behavioral treatments.

Within a behavioral self-management treatment program for overweight, 59 patients were randomly assigned to receive as an adjunct either dextroamphetamine sulfate, fenfluramine hydrochloride, or placebo in a double-blind procedure. Patients self-regulated their drug intake during a four-week medication period. Two types of behavioral-pharmacological interaction were observed: (1) drug assignment influenced participation in the behavioral treatment; and (2) drug assignment influenced the extent of medication self-administration. The dextroamphetamine group was superior in terms of behavioral treatment participation, extent of eating and exercise habit change, and weight loss. Self-administration of dextroamphetamine was most well-maintained--showing it to be a reinforcer--and self-administration of fenfluramine was suppressed below placebo levels. No patient taking either drug showed excessive drug intake, and all were, in fact, conservative in drug use. These data concerning relative reinforcing efficacy within a therapeutic medication setting are discussed in relation to data from animal models used to assess relative abuse liability of these drugs.

Adult↗
PubMed1980

Effects of ventilated cigarette holders on cigarette smoking by humans.

Heavy cigarette smokers individually attended daily 3-h test sessions which were run in specially designed cigarette smoking evaluation rooms. Subjects were required to use the cigarette holder provided, and were required to extinguish each cigarette 4 min after the first puff on the cigarette. Other than these restrictions, subjects were allowed to smoke ad libitum. The concentration of delivered tobacco product was varied from 100 to 10% across sessions by using graded commercially available ventilated cigarette holders. As concentration of tobacco product was decreased, rate of puffing and total number of puffs showed robust compensatory increases. Number of cigarettes increased only moderately in response to decreases in tobacco product concentration. There was little change in subjective ratings of strength on smoking satisfaction. Finally, expired air carbon monoxide (CO) values and cigarette butt weights were relatively stable across the four ventilation conditions. These later findings suggest that a significant degree of compensation had occurred in response to the concentration manipulations.

Adolescent↗
PubMed1980

An inexpensive portable device for measuring puffing behavior by cigarette smokers.

A device for counting discrete puffs by cigarette smokers is inexpensive, easily constructed, and fully portable. The device consists of a plastic cigarette holder which is connected to a miniature pressure sensor via 18 gauge polyvinyl tubing. The pressure sensor has two electrical terminals which provide access to a normally open circuit which is closed following a pressure drop produced by puffing on the cigarette holder. The pressure sensor is wired to a common pocket calculator in such a way that each puff is counted by the calculator. The device has been shown to be reliable, and the puff measure is sensitive to a variety of experimental manipulations. The device may serve in either the laboratory setting or may be carried by a smoker to monitor his behavior in his natural environment.

Behavior↗
PubMed1980

Drug preference in humans: double-blind choice comparison of pentobarbital, diazepam and placebo.

In a residential hospital research ward setting the effects of and preference for placebo and various oral doses of pentobarbital and diazepam were studied in volunteer human subjects with documented histories of sedative abuse. Drug-free days alternated with drug administration days throughout the study. After experimenter-scheduled exposures to the test drugs, subjects were given repeated opportunities to choose between two available drug alternatives. In experiment 1, pentobarbital (200-900 mg) produced dose-related increases in subject- and observer-rated drug effects, and subjects generally chose higher pentobarbital doses over lower doses. In experiment 2, diazepam (50-400 mg) produced only modest elevations in drug effect ratings and subjects did not consistently choose higher doses over lower doses. In experiment 3, 400 mg of pentobarbital and 200 mg of diazepam produced subject and observer drug effect ratings of similar magnitude while placebo produced negligible effects. All subjects chose pentobarbital over placebo and diazepam over placebo on all occasions; all subjects chose pentobarbital over diazepam on the majority of choice trials. Clinical impression confirmed by a post hoc analysis of nursing notes indicated that diazepam produced relatively subtle yet reliable changes in the global mood and behavior of the subjects in the direction of increased complaining, dysphoria and disruptivenes. The finding that pentobarbital is preferred to diazepam is compatible with previous human and animal drug self-administration studies as well as clinical information about the abuse of these drugs.

Adult↗
PubMed1979

Opioids: similarity between evaluations of subjective effects and animal self-administration results.

Abuse potential studies of 33 morphine-like analgesics were compared in humans and monkeys. The results of intravenous self-administration studies in rhesus monkeys were correlated with measures of morphine-like signs, symptoms, and subjective effects in ex-addicts. Each set of data was assigned to a position in a 3 x 3 contingency table dependent upon whether the results were yes, no, or equivocal. Of the 33 drugs, 29 were given identical classifications in both the human and animal test procedures. This good concordance between the human and animal results further validates each procedure and suggests the possibility that both the human and animal procedures are measuring a common underlying pharmacological property which relates to abuse potential of drugs.

Animals↗
PubMed1979

Progressive ratio and fixed ratio schedules of cocaine-maintained responding in baboons.

Responding maintained under progressive ratio (PR) and fixed ratio (FR 160) schedules of IV saline or cocaine (0.01-4.0 mg/kg) injections was studied in baboons. Each injection was followed by a time-out period which was 3-h with the PR schedule and was either 3 or 12 with the FR schedule. On the PR schedule the ratio requirement was systematically increased each day until reaching the 'breaking point' at which self-injection performance fell below a criterion level (one or zero injections per day). Overall response rates on the PR schedule increased with progressive increases in the ratio until a maximum at which an abrupt reduction in responding occurred. With the 3-h time-out the dose-breaking point function on the PR schedule was similar to the dose-response rate function on the FR schedule. These dose-effect functions were inverted U-shaped curves characterized by a graded ascending limb (0.01-0.32 mg/kg) and a downturn at the highest doses (3.0-4.0 mg/kg). On the FR schedule the downturn in the dose-response rate function was attributable to a cumulative drug effect as revealed by manipulation of time-out duration and analysis of sequential interresponse time distributions and cumulative response records. PR and FR schedules provide similar information about the relative reinforcing efficacy of different cocaine doses.

Animals↗
PubMed1978

Effects of d-amphetamine on speaking in isolated humans.

The effects of oral d-amphetamine, 5--20 mg were studied in isolated humans who produced speech monologues during experimental sessions. Drug effects were studied under double-blind conditions by making repeated observations within each subject after placebo or active drug. In the first experiment, d-amphetamine 15 mg was studied in 4 isolated subjects who had received instructions that they should talk some of the time during experimental sessions. All subjects spoke more after active drug than after placebo. In the second experiment, d-amphetamine 5--20 mg was studied in 4 subjects who were instructed to talk, but who also earned points under a fixed interval 5 min schedule by speaking (i.e. by closure of a voice operated relay). Point delivery did not generally influence patterns of speech over time. Reliable drug produced increases in amount of talking were observed in 3 of 4 subjects. Adjective checklist self report scores indicating a stimulant drug effect were also sensitive to effects of d-amphetamine. Under controlled laboratory conditions, an increase in speaking is a reliable behavioral effect of d-amphetamine in isolated humans producing speech monologues.

Adult↗