Delay or probability discounting in a model of impulsive behavior: effect of alcohol.
Little is known about the acute effects of drugs of abuse on impulsivity and self-control. In this study, impulsivity was assessed in humans using a computer task that measured delay and probability discounting. Discounting describes how much the value of a reward (or punisher) is decreased when its occurrence is either delayed or uncertain. Twenty-four healthy adult volunteers ingested a moderate dose of ethanol (0.5 or 0.8 g/kg ethanol: n = 12 at each dose) or placebo before completing the discounting task. In the task the participants were given a series of choices between a small, immediate, certain amount of money and $10 that was either delayed (0, 2, 30, 180, or 365 days) or probabilistic (i.e., certainty of receipt was 1.0, .9, .75, .5, or .25). The point at which each individual was indifferent between the smaller immediate or certain reward and the $10 delayed or probabilistic reward was identified using an adjusting-amount procedure. The results indicated that (a) delay and probability discounting were well described by a hyperbolic function; (b) delay and probability discounting were positively correlated within subjects; (c) delay and probability discounting were moderately correlated with personality measures of impulsivity; and (d) alcohol had no effect on discounting. (+info)
Different contributions of the human amygdala and ventromedial prefrontal cortex to decision-making.
The somatic marker hypothesis proposes that decision-making is a process that depends on emotion. Studies have shown that damage of the ventromedial prefrontal (VMF) cortex precludes the ability to use somatic (emotional) signals that are necessary for guiding decisions in the advantageous direction. However, given the role of the amygdala in emotional processing, we asked whether amygdala damage also would interfere with decision-making. Furthermore, we asked whether there might be a difference between the roles that the amygdala and VMF cortex play in decision-making. To address these two questions, we studied a group of patients with bilateral amygdala, but not VMF, damage and a group of patients with bilateral VMF, but not amygdala, damage. We used the "gambling task" to measure decision-making performance and electrodermal activity (skin conductance responses, SCR) as an index of somatic state activation. All patients, those with amygdala damage as well as those with VMF damage, were (1) impaired on the gambling task and (2) unable to develop anticipatory SCRs while they pondered risky choices. However, VMF patients were able to generate SCRs when they received a reward or a punishment (play money), whereas amygdala patients failed to do so. In a Pavlovian conditioning experiment the VMF patients acquired a conditioned SCR to visual stimuli paired with an aversive loud sound, whereas amygdala patients failed to do so. The results suggest that amygdala damage is associated with impairment in decision-making and that the roles played by the amygdala and VMF in decision-making are different. (+info)
Physiological changes in Pachinko players; beta-endorphin, catecholamines, immune system substances and heart rate.
Pachinko is a popular form of recreation in Japan. However, in recent years, along with Pachinko's popularity, "Pachinko dependence" has become topical news. The purpose of this study was to investigate beta-endorphin, catecholamines, immune system responses and heart rate during the playing of Pachinko. The following significant results were observed. (1) Plasma concentration of beta-endorphin increased before playing Pachinko and while in the Pachinko-center (p < 0.05). (2) Beta-endorphin and norepinephrine increased when the player began to win (i.e. at "Fever-start") compared to baseline (p < 0.05). (3) Beta-endorphin, norepinephrine and dopamine increased when the winning streak finished (i.e. at "Fever-end") compared to baseline (p < 0.05-0.01). (4) Norepinephrine increased past 30 minutes after "Fever-end" compared to baseline (p < 0.05). (5) Heart rate increased before "Fever-start" compared to baseline, peaked at "Fever-start" and rapidly decreased to match rates measured at rest. But the increase was observed from 200 seconds after "Fever-start" (p < 0.05-0.001). (6) There was a positive correlation between the number of hours subjects played Pachinko in a week and the differences between beta-endorphin levels at "Fever-start" and those at rest (p < 0.05). (7) The number of T-cells decreased while the number of NK cells increased at "Fever-start" compared to baseline (p < .05). These results suggest that intracerebral substances such as beta-endorphin and dopamine are involved in the habit-forming behavior associated with Pachinko. (+info)
Estimating the prevalence of disordered gambling behavior in the United States and Canada: a research synthesis.
OBJECTIVES: This study developed prevalence estimates of gambling-related disorders in the United States and Canada, identified differences in prevalence among population segments, and identified changes in prevalence over the past 20 years. METHODS: A meta-analytic strategy was employed to synthesize estimates from 119 prevalence studies. This method produced more reliable prevalence rates than were available from any single study. RESULTS: Prevalence estimates among samples of adolescents were significantly higher than estimates among samples of adults for both clinical (level 3) and subclinical (level 2) measures of disordered gambling within both lifetime and past-year time frames (e.g., 3.9% vs 1.6% for lifetime estimates of level 3 gambling). Among adults, prevalence estimates of disordered gambling have increased significantly during the past 20 years. CONCLUSIONS: Membership in youth, treatment, or prison population segments is significantly associated with experiencing gambling-related disorders. Understanding subclinical gamblers provides a meaningful opportunity to lower the public health burden associated with gambling disorders. Further research is necessary to determine whether the prevalence of disordered gambling will continue to increase among the general adult population and how prevalence among adolescents will change as this cohort ages. (+info)
Are decisions under risk malleable?
Human decision making under risk and uncertainty may depend on individual involvement in the outcome-generating process. Expected utility theory is silent on this issue. Prospect theory in its current form offers little, if any, prediction of how or why involvement in a process should matter, although it may offer ex post interpretations of empirical findings. Well-known findings in psychology demonstrate that when subjects exercise more involvement or choice in lottery procedures, they value their lottery tickets more highly. This often is interpreted as an "illusion of control," meaning that when subjects are more involved in a lottery, they may believe they are more likely to win, perhaps because they perceive that they have more control over the outcome. Our experimental design eliminates several possible alternative explanations for the results of previous studies in an experiment that varies the degree and type of involvement in lottery procedures. We find that in treatments with more involvement subjects on average place less rather than more value on their lottery tickets. One possible explanation for this is that involvement interacts with loss aversion by causing subjects to weigh losses more heavily than they would otherwise. One implication of our study is that involvement, either independently or in interaction with myopic loss aversion, may help explain the extreme risk aversion of bond investors. (+info)
Pathologic gambling and problem gambling affect approximately 5 to 15 million Americans and are common in young people. The community-minded family physician is in a good position to identify and assist patients who have gambling-related problems and thereby prevent or treat the resultant personal, family and social disruptions. Provider and community education about the depth and breadth of this condition is crucial for the identification and treatment of a growing problem. As with many psychologic conditions, identification of the disorder and treatment of the patient by the family physician comprise the primary treatment. Screening tools, treatment programs and self-help groups provide additional resources for the family physician. An illustrative case report demonstrates the importance of heightened awareness of and screening for this common condition. (+info)
Identifying problem and compulsive gamblers.
OBJECTIVE: To present a meta-analysis of current research on the prevalence, identification, and treatment of problem and compulsive gamblers. QUALITY OF EVIDENCE: Problem and compulsive gambling was not a socio-scientific concern until the last two decades. Hence research on this topic is limited. The summary and analysis for this paper relied on computer searches of journal and news abstracts in addition to direct contact with organizations addressing the identification and treatment of compulsive gamblers. MAIN MESSAGE: An estimated 5% of those who gamble run into problems. About 1% of those who gamble are predicted to experience serious problems. Successful treatment of problem and compulsive gambling continues to be a challenge. Although cognitive therapy has been the favoured approach, a combination of several therapeutic approaches is advocated. CONCLUSIONS: Problem and compulsive gambling can present a real health threat. As with other addictions, treatment strategies continue to be a baffling social problem. Aware and informed physicians can have a pivotal role in the difficult process of identifying, acknowledging, and remediating problem and compulsive gambling. (+info)
Expansion of gambling in Canada: implications for health and social policy.
Canada experienced a dramatic increase in legalized gambling in the 1990s, primarily because of governments' need to increase revenue without additional taxation. This article examines gambling from a public health perspective. The major public health issues include gambling addiction, family dysfunction and gambling by youth. Debates have emerged about the health, social and economic costs and benefits of gambling. Stakeholder and social policy groups have expressed concern about the impact of expanded gambling on the quality of life of individuals, families and communities. Epidemiological studies show that the prevalence of gambling in the general adult population is low but increasing. Of particular concern is the high though steady prevalence of gambling among youth. New technologies have been linked to gambling-related problems such as addiction to gambling by video lottery terminals. Gambling by means of the Internet represents another emerging issue. The article concludes with recommendations for health and social policy related to gambling. These recommendations incorporate a broad public health approach to create a strong research program and to balance risks and benefits. (+info)