Biomedical subjects

L A Marsch

Publications and source records attributed to L A Marsch.

7 recordsLinked to original sources

PubMed2001

Development and validation of the situational self-awareness scale.

This article discusses the manipulation and measurement of levels of situational self-focus, which is generally labeled "self-awareness." A new scale was developed to quantify levels of public and private self-awareness. Five studies were conducted to assess the psychometric properties, reliability, and validity of the Situational Self-Awareness Scale (SSAS). The SSAS was found to have a reliable factor structure, to detect differences in public and private self-awareness produced by laboratory manipulations, and to be sensitive to changes in self-awareness within individuals over time and across situations. The SSAS can be used as a manipulation check of laboratory self-awareness manipulations and as a means of assessing naturally occurring fluctuations in public and private self-awareness in order to clarify the relation between self-awareness and other variables (e.g., mood and memory).

Adolescent↗

PubMed2001

Toward a behavioral economic understanding of drug dependence: delay discounting processes.

Behavioral economics examines conditions that influence the consumption of commodities and provides several concepts that may be instrumental in understanding drug dependence. One such concept of significance is that of how delayed reinforcers are discounted by drug dependent individuals. Discounting of delayed reinforcers refers to the observation that the value of a delayed reinforcer is discounted (reduced in value or considered to be worth less) compared to the value of an immediate reinforcer. This paper examines how delay discounting may provide an explanation of both impulsivity and loss of control exhibited by the drug dependent. In so doing, the paper reviews economic models of delay discounting, the empirical literature on the discounting of delayed reinforcers by the drug dependent and the scientific literature on personality assessments of impulsivity among drug-dependent individuals. Finally, future directions for the study of discounting are discussed, including the study of loss of control and loss aversion among drug-dependent individuals, the relationship of discounting to both the behavioral economic measure of elasticity as well as to outcomes observed in clinical settings, and the relationship between impulsivity and psychological disorders other than drug dependence.

Humans↗

PubMed2001

Effects of infusion rate of intravenously administered morphine on physiological, psychomotor, and self-reported measures in humans.

Although the rate of onset of a drug effect is commonly believed to contribute to a drug's abuse liability, only a few systematic experimental studies have been conducted examining this notion. The present study determined the profile of physiological, psychomotor, and self-reported effects of infusion rate (a key means of manipulating onset of drug action) of intravenously administered morphine, the prototypical analgesic with a known abuse liability in human participants. Two doses of morphine sulfate (5 and 10 mg/70 kg, i.v.) and a placebo dose (0 mg/70 kg, i.v.) were administered to healthy volunteers under three infusion rates (2 min bolus, 15 min, and 60 min). Faster infusions of morphine produced greater positive subjective effects than slower infusions on visual analog scale measures of good drug effect, drug liking, and high. Faster infusions also resulted in greater self-reported drug effects and opioid agonist effects, without producing significant physiological or psychomotor impairment. Importantly, faster rates of drug infusion produced significantly higher morphine plasma levels than slower rates, and morphine plasma levels followed a similar pattern and timing of peak effect as the self-reported effects of the drug. Moreover, morphine produced dose-dependent increases in self-reported drug effects, opioid agonist effects, and morphine plasma levels in the study. Results suggest that the pharmacokinetic properties of a drug, including the dosage administered and the rate of at which it is administered may function to jointly affect the abuse liability of the drug.

Adolescent↗

PubMed2000

Deconstructing relative reinforcing efficacy and situating the measures of pharmacological reinforcement with behavioral economics: a theoretical proposal.

BACKGROUND: Relative reinforcing efficacy has been assumed to be a homogeneous phenomenon referring to the behavior-strengthening or behavior-maintaining effects of a drug reinforcer. However, a variety of studies suggest that relative reinforcing efficacy may be heterogeneous. OBJECTIVES: The purpose of this theoretical proposal is to examine the difficulties associated with this conception of reinforcing efficacy and to explore whether relative reinforcing efficacy is a homogenous concept or whether it is composed of several functionally related heterogeneous phenomena. In examining this issue, we explore whether behavioral economic theory may address some of the challenges to the current conception of relative reinforcing efficacy and use this theory to suggest how the differing measures of reinforcing efficacy may relate to one another. RESULTS: Results indicate that peak-response rate and breakpoint are related to the economic measure of maximal output and elasticity of demand, respectively. Preference is related to and predicted by the relative location of the demand curves obtained under single schedule conditions. This behavioral economic analysis may provide a theoretical understanding of reinforcement that can reconcile results of studies that both support and fail to support the notion of reinforcing efficacy as a homogenous phenomenon. CONCLUSIONS: If this theoretical proposal is validated by additional studies, then like other natural phenomena found to be heterogeneous, the study of drug reinforcers may require the adoption of several new scientific terms, such as those used in behavioral economics, each of which has analytical precision and refers to homogeneous phenomena.

Animals↗

PubMed2000

Elevated liver enzyme levels in opioid-dependent patients with hepatitis treated with buprenorphine.

The purpose of this study was to assess changes in liver enzyme levels among opioid-dependent patients treated with buprenorphine. Liver enzyme levels were evaluated among 120 individuals before treatment and following a minimum of 40 days of buprenorphine treatment (2, 4, or 8 mg/70 kg/day). Among patients with a history of hepatitis, AST and ALT levels significantly increased (p < .05) with buprenorphine treatment. The odds of observing an increase in AST were determined to be dependent upon buprenorphine dose (p < .05; odds ratio = 1.23 per 1 mg increase in dose). These results suggest that liver enzyme levels should be monitored carefully when patients with hepatitis are treated with buprenorphine.

Adult↗

PubMed1998

The efficacy of methadone maintenance interventions in reducing illicit opiate use, HIV risk behavior and criminality: a meta-analysis.

AIMS: To provide empirically based evaluation data regarding the efficacy of psychopharmacological interventions in opiate substance abuse, the present study employed meta-analytic statistical procedures to determine the effectiveness of methadone hydrochloride as a pharmacotherapeutic agent. DESIGN: Empirical research findings from 11 studies investigating the effect of methadone maintenance treatment (MMT) on illicit opiate use, and eight and 24 studies investigating the effect of MMT on HIV risk behaviors and criminal activities, respectively, by individuals in such treatment were addressed. FINDINGS: Results demonstrate a consistent, statistically significant relationship between MMT and the reduction of illicit opiate use, HIV risk behaviors and drug and property-related criminal behaviors. The effectiveness of MMT is most apparent in its ability to reduce drug-related criminal behaviors. MMT had a moderate effect in reducing illicit opiate use and drug and property-related criminal behaviors, and a small to moderate effect in reducing HIV risk behaviors. CONCLUSIONS: Results clarify discrepancies in the literature and are useful in predicting the outcomes of individuals in treatment. The treatment's effectiveness is evident among opiate-dependent individuals across a variety of contexts, cultural and ethnic groups, and study designs.

Crime↗

PubMed1997

Inducing positive mood without demand characteristics.

The possibility that a state of private self-awareness induced by a small mirror can facilitate the effect of procedures which induce a positive mood was investigated. Participants were 171 female and 60 male undergraduates who were randomly assigned to one of six conditions in a 2 (Mirror vs No-mirror) x 3 (Control vs Velten manipulation vs Music manipulation) design. As predicted, participants who experienced the Velten and Music manipulations in the presence of the mirror reported elevated mood relative to control participants. The mood of participants who experienced the Velten and Music manipulations without the mirror did not differ from the mood of control participants. The potential benefits of using a small mirror as a substitute for explicit instructions about the expected effect of mood-induction procedures are discussed.

Adolescent↗