scholarly journals Computational psychiatry of impulsivity and risk: how risk and time preferences interact in health and disease

2018 ◽  
Vol 374 (1766) ◽  
pp. 20180135 ◽  
Author(s):  
Silvia Lopez-Guzman ◽  
Anna B. Konova ◽  
Paul W. Glimcher
Keyword(s):  
Risk Taking ◽  
Temporal Discounting ◽  
Time Preferences ◽  
Clinical Implications ◽  
Mathematical Relationship ◽  
Theme Issue ◽  
Impulsive Behaviour ◽  
Theoretical Perspectives ◽  
Subjective Value ◽  
Health And Disease

Choice impulsivity is an important subcomponent of the broader construct of impulsivity and is a key feature of many psychiatric disorders. Choice impulsivity is typically quantified as temporal discounting , a well-documented phenomenon in which a reward's subjective value diminishes as the delay to its delivery is increased. However, an individual's proclivity to—or more commonly aversion to— risk can influence nearly all of the standard experimental tools available for measuring temporal discounting. Despite this interaction, risk preference is a behaviourally and neurobiologically distinct construct that relates to the economic notion of utility or subjective value. In this opinion piece, we discuss the mathematical relationship between risk preferences and time preferences, their neural implementation, and propose ways that research in psychiatry could, and perhaps should, aim to account for this relationship experimentally to better understand choice impulsivity and its clinical implications. This article is part of the theme issue ‘Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications’.

scholarly journals Conquering the inner couch potato: precommitment is an effective strategy to enhance motivation for effortful actions

2018 ◽  
Vol 374 (1766) ◽  
pp. 20180131 ◽  
Author(s):  
Bettina Studer ◽  
Carolin Koch ◽  
Stefan Knecht ◽  
Tobias Kalenscher
Keyword(s):  
Risk Taking ◽  
Small Reward ◽  
Computational Modelling ◽  
Self Control ◽  
Clinical Implications ◽  
Theme Issue ◽  
Choice Behaviour ◽  
Impulsive Behaviour ◽  
Theoretical Perspectives ◽  
Regulatory Measure

Letting effort-free gratification derail us from effort-requiring goals is one reason why we fail to realize health-relevant intentions like ‘exercise regularly’. We tested the effectiveness of the self-control strategy precommitment in such effort-related conflicts, using a novel laboratory choice paradigm, where participants could precommit to an effort-requiring large reward by pre-eliminating an effort-free small reward from their choice set. Our participants used precommitment frequently and effectively, such that they reached effort-requiring large rewards more often. Using computational modelling and Bayesian model comparisons, we assessed whether participants employed precommitment to avoid anticipated willpower failures (i.e. as a self-regulatory measure) or to maximize their motivation to choose the effort-requiring option (i.e. as a self-motivational measure). Observed choices and precommitment decisions were consistent with the motivation maximization hypothesis, but not the willpower hypothesis. Our findings show that offering precommitment is effective in helping individuals optimize their motivation and choice behaviour and thereby achieve effort-requiring goals, and strongly encourage application of precommitment schemes in exercise and rehabilitation interventions. This article is part of the theme issue ‘Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications’.

scholarly journals Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications

2018 ◽  
Vol 374 (1766) ◽  
pp. 20180128 ◽  
Author(s):  
Anthony R. Isles ◽  
Catharine A. Winstanley ◽  
Trevor Humby
Keyword(s):  
Obsessive Compulsive Disorder ◽  
Risk Taking ◽  
Neurodegenerative Disorders ◽  
Human Population ◽  
Clinical Implications ◽  
Theme Issue ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
Impulsive Behaviour ◽  
Theoretical Perspectives

Our willingness to take risks, our ability to wait or the speed with which to make decisions are central features of our personality. However, it is now recognized that impulsive and risk-taking behaviours are not a unitary construct, and different aspects can be both psychologically and neurally dissociated. The range of neurochemicals and brain systems that govern these behaviours is extensive, and this may be a contributing factor to the phenotypic range seen in the human population. However, this variety can also be pathological as extremes in risk-taking and impulsive behaviours are characteristics of many neuropsychiatric and indeed neurodegenerative disorders. This spans obsessive–compulsive disorder, where behaviour becomes ridged and non-spontaneous, to the nonsensical risk-taking seen in gambling and drug taking. This article is part of the theme issue ‘Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications'.

scholarly journals Interactions of immediate and long-term action regulation in the course and complications of bipolar disorder

2018 ◽  
Vol 374 (1766) ◽  
pp. 20180132 ◽  
Author(s):  
Marijn Lijffijt ◽  
Brittany O'Brien ◽  
Ramiro Salas ◽  
Sanjay J. Mathew ◽  
Alan C. Swann
Keyword(s):  
Bipolar Disorder ◽  
Risk Taking ◽  
Treatment Strategies ◽  
Behavioural Disorders ◽  
Theme Issue ◽  
Impulsive Behaviour ◽  
Behavioural Sensitization ◽  
Theoretical Perspectives ◽  
Clinical Consequences

Immediate and long-term mechanisms interact in the regulation of action. We will examine neurobiology and practical clinical consequences of these interactions. Long-term regulation of immediate behavioural control is based on analogous responses to highly rewarding or stressful stimuli: (i) impulsivity is a failure of the balance between activation and inhibition in the immediate regulation of action. (ii) Sensitization is a persistently exaggerated behavioural or physiological response to highly salient stimuli, such as addictive stimuli or inescapable stress. Sensitization can generalize across classes of stimuli. (iii) Impulsivity, possibly related to poor modulation of catecholaminergic and glutamatergic functions, may facilitate development of long-term sensitized responses to stressful or addictive stimuli. In turn, impulsivity is prominent in sensitized behaviour. (iv) While impulsivity and sensitization are general components of behaviour, their interactions are prominent in the course of bipolar disorder, emphasizing roles of substance-use, recurrent course and stressors. (v) Suicide is a complex and severe behaviour that exemplifies the manner in which impulsivity facilitates behavioural sensitization and is, in turn, increased by it, leading to inherently unpredictable behaviour. (vi) Interactions between impulsivity and sensitization can provide targets for complementary preventive and treatment strategies for severe immediate and long-term behavioural disorders. Progress along these lines will be facilitated by predictors of susceptibility to behavioural sensitization. This article is part of the theme issue ‘Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications’.

scholarly journals Why has evolution not selected for perfect self-control?

2018 ◽  
Vol 374 (1766) ◽  
pp. 20180139 ◽  
Author(s):  
Benjamin Y. Hayden
Keyword(s):  
Cognitive Control ◽  
Risk Taking ◽  
Decision Makers ◽  
Self Control ◽  
Subjective Feeling ◽  
Theme Issue ◽  
Theoretical Perspectives ◽  
Obvious Reason ◽  
Control Failures

Self-control refers to the ability to deliberately reject tempting options and instead select ones that produce greater long-term benefits. Although some apparent failures of self-control are, on closer inspection, reward maximizing, at least some self-control failures are clearly disadvantageous and non-strategic. The existence of poor self-control presents an important evolutionary puzzle because there is no obvious reason why good self-control should be more costly than poor self-control. After all, a rock is infinitely patient. I propose that self-control failures result from cases in which well-learned (and thus routinized) decision-making strategies yield suboptimal choices. These mappings persist in the decision-makers’ repertoire because they result from learning processes that are adaptive in the broader context, either on the timescale of learning or of evolution. Self-control, then, is a form of cognitive control and the subjective feeling of effort likely reflects the true costs of cognitive control. Poor self-control, in this view, is ultimately a result of bounded optimality. This article is part of the theme issue ‘Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications.

scholarly journals Feeding behaviour, risk-sensitivity and response control: effects of 5-HT2Creceptor manipulations

2018 ◽  
Vol 374 (1766) ◽  
pp. 20180144 ◽  
Author(s):  
Trevor Humby ◽  
Yateen Patel ◽  
Jenny Carter ◽  
Laura-Jean G. Stokes ◽  
Robert D. Rogers ◽  
...  
Keyword(s):  
Risk Taking ◽  
Impulse Control ◽  
Delay Condition ◽  
Risk Sensitivity ◽  
Variable Delay ◽  
Theme Issue ◽  
The Past ◽  
Theoretical Perspectives ◽  
Developed World ◽  
The Impact

People, like animals, tend to choose the variable option when given the choice between a fixed and variable delay to reward where, in the variable delay condition, some rewards are available immediately (Laura-Jeanet al. 2019Phil. Trans. R. Soc. B374, 20180141. (doi:10.1098/rstb.2018.0141)). This bias has been suggested to reflect evolutionary pressures resulting from food scarcity in the past placing a premium on obtaining food quickly that can win out against the risks of sometimes sustaining longer delays to food. The psychologies mediating this effect may become maladaptive in the developed world where food is readily available contributing, potentially, to overeating and obesity. Here, we report our development of a novel touchscreen task in mice allowing comparisons of the impact of food delay and food magnitude across species. We show that mice exhibit the typical preference, as shown by humans, for variable over fixed delays to rewards but no preference when it comes to fixed versus variable reward amounts and further show that this bias is sensitive to manipulations of the 5-HT2Creceptor, a key mediator of feeding and impulse control. We discuss the data in terms of the utility of the task to model the psychologies and underlying brain mechanisms impacting on feeding behaviours.This article is part of the theme issue ‘Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications’.

scholarly journals Relationships among impulsive, addictive and sexual tendencies and behaviours: a systematic review of experimental and prospective studies in humans

2018 ◽  
Vol 374 (1766) ◽  
pp. 20180129 ◽  
Author(s):  
Robert F. Leeman ◽  
Bonnie H. P. Rowland ◽  
Nioud Mulugeta Gebru ◽  
Marc N. Potenza
Keyword(s):  
Sexual Behaviour ◽  
Risk Taking ◽  
Empirical Support ◽  
International Classification Of Diseases ◽  
Impulsive Behaviour ◽  
Sexual Behaviours ◽  
Theoretical Perspectives ◽  
Wide Range ◽  
Classification Of Diseases

Impulsivity's relationships to addictive and sexual behaviours raise questions regarding the extent impulsivity may constitute a vulnerability factor for subsequent addictive and sexual behaviours and/or results from each of these. Here, we systematically reviewed empirical support for impulsivity as a precipitating factor or a consequence of addictive or sexual behaviours. We restricted ourselves to recent, human studies with assessments over time, including at least one measure of impulsivity, addictive and sexual behaviours, yielding a review including 29 published reports from 28 studies. Findings point to generalized, self-reported impulsivity as a predictor of addictive and sexual behaviours at a wide range of severity, with elements of both impulsivity and compulsivity to these acts. Alcohol consumption often increases impulsive behaviour, including inclinations towards impulsive and potentially compulsive sexual acts. Research using the Sexual Delay Discounting Task has yielded findings linking impulsivity, addictive and sexual behaviour and as such is a valuable research tool that should be used more extensively. The present review identified gaps to be addressed in further research that concurrently examines facets of impulsivity, addictive and sexual behaviours, especially because criteria for compulsive sexual behaviour disorder have been included in the eleventh edition of the International Classification of Diseases . This article is part of the theme issue ‘Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications’.

Dissecting the Effects of Disease and Treatment on Impulsivity in Parkinson's Disease

2012 ◽  
Vol 18 (6) ◽  
pp. 942-951 ◽  
Author(s):  
Alison C. Simioni ◽  
Alain Dagher ◽  
Lesley K. Fellows
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Disease Progression ◽  
Risk Taking ◽  
Temporal Discounting ◽  
Baseline Risk ◽  
Neural Basis ◽  
Risky Decision ◽  
Balloon Analogue Risk Task

AbstractConverging evidence, including observations in patients with Parkinson's disease (PD), suggests that dopamine plays a role in impulsivity. This multi-faceted construct includes considerations of both time and risk; determining how these more specific processes are affected by PD and dopaminergic treatment can inform neurobiological models. We examined the effects of PD and its treatment on temporal discounting and risky decision-making in a cohort of 23 mild-moderate PD patients and 20 healthy participants. Patients completed the Balloon Analogue Risk Task and a temporal discounting paradigm both on and off their usual dopamine replacement therapy. PD patients did not differ from controls in their initial risk-taking on the Balloon Analogue Risk Task, but took progressively more risks across trials when on medication. A subset of patients and controls was tested again, 1.5–3 years later, to explore the effects of disease progression. On follow-up, baseline risk-taking diminished in patients, but the tendency to take increasing risks across trials persisted. Neither disease progression nor its treatment affected the temporal discounting rate. These findings suggest a different neural basis for temporal discounting and risk-taking, and demonstrate that risk-taking can be further decomposed into initial and trial-by-trial effects, with dopamine affecting only the latter. (JINS, 2012, 18, 1–10)

scholarly journals Arginine Derivatives in Cerebrovascular Diseases: Mechanisms and Clinical Implications

2020 ◽  
Vol 21 (5) ◽  
pp. 1798 ◽  
Author(s):  
Gerrit M. Grosse ◽  
Edzard Schwedhelm ◽  
Hans Worthmann ◽  
Chi-un Choe
Keyword(s):  
Ischemic Stroke ◽  
Vascular Function ◽  
Cerebrovascular Diseases ◽  
Current Evidence ◽  
Clinical Implications ◽  
Pathophysiological Role ◽  
Health And Disease ◽  
Oxide Synthase ◽  
Derivatives Of

The amino acid L-arginine serves as substrate for the nitric oxide synthase which is crucial in vascular function and disease. Derivatives of arginine, such as asymmetric (ADMA) and symmetric dimethylarginine (SDMA), are regarded as markers of endothelial dysfunction and have been implicated in vascular disorders. While there is a variety of studies consolidating ADMA as biomarker of cerebrovascular risk, morbidity and mortality, SDMA is currently emerging as an interesting metabolite with distinct characteristics in ischemic stroke. In contrast to dimethylarginines, homoarginine is inversely associated with adverse events and mortality in cerebrovascular diseases and might constitute a modifiable protective risk factor. This review aims to provide an overview of the current evidence for the pathophysiological role of arginine derivatives in cerebrovascular ischemic diseases. We discuss the complex mechanisms of arginine metabolism in health and disease and its potential clinical implications in diverse aspects of ischemic stroke.

scholarly journals Estimating molecular preservation of the intestinal microbiome via metagenomic analyses of latrine sediments from two medieval cities

2020 ◽  
Vol 375 (1812) ◽  
pp. 20190576 ◽  
Author(s):  
Susanna Sabin ◽  
Hui-Yuan Yeh ◽  
Aleks Pluskowski ◽  
Christa Clamer ◽  
Piers D. Mitchell ◽  
...  
Keyword(s):  
Gut Microbiome ◽  
Intestinal Flora ◽  
Population Level ◽  
Intestinal Microbiome ◽  
Bulk Sediment ◽  
Theme Issue ◽  
Gastrointestinal Health ◽  
Health And Disease ◽  
The Rich ◽  
Microbial Dna

Ancient latrine sediments, which contain the concentrated collective biological waste of past whole human communities, have the potential to be excellent proxies for human gastrointestinal health on the population level. A rich body of literature explores their use to detect the presence of gut-associated eukaryotic parasites through microscopy, immunoassays and genetics. Despite this interest, a lack of studies have explored the whole genetic content of ancient latrine sediments through consideration not only of gut-associated parasites, but also of core community gut microbiome signals that remain from the group that used the latrine. Here, we present a metagenomic analysis of bulk sediment from medieval latrines in Riga (Latvia) and Jerusalem. Our analyses reveal survival of microbial DNA representative of intestinal flora as well as numerous parasites. These data are compared against parasite taxon identifications obtained via microscopy and ELISA techniques. Together, these findings provide a first glimpse into the rich prokaryotic and eukaryotic intestinal flora of pre-industrial agricultural populations, which may give a better context for interpreting the health of modern microbiomes. This article is part of the theme issue ‘Insights into health and disease from ancient biomolecules’.

scholarly journals Uncertainty and computational complexity

2018 ◽  
Vol 374 (1766) ◽  
pp. 20180138 ◽  
Author(s):  
Peter Bossaerts ◽  
Nitin Yadav ◽  
Carsten Murawski
Keyword(s):  
Decision Making ◽  
Computational Complexity ◽  
Risk Taking ◽  
Utility Maximization ◽  
Decision Makers ◽  
Primary Concern ◽  
Subjective Beliefs ◽  
Theoretical Perspectives ◽  
New Information ◽  
Savage Axioms

Modern theories of decision-making typically model uncertainty about decision options using the tools of probability theory. This is exemplified by the Savage framework, the most popular framework in decision-making research. There, decision-makers are assumed to choose from among available decision options as if they maximized subjective expected utility, which is given by the utilities of outcomes in different states weighted with subjective beliefs about the occurrence of those states. Beliefs are captured by probabilities and new information is incorporated using Bayes’ Law. The primary concern of the Savage framework is to ensure that decision-makers’ choices are rational . Here, we use concepts from computational complexity theory to expose two major weaknesses of the framework. Firstly, we argue that in most situations, subjective utility maximization is computationally intractable, which means that the Savage axioms are implausible. We discuss empirical evidence supporting this claim. Secondly, we argue that there exist many decision situations in which the nature of uncertainty is such that (random) sampling in combination with Bayes’ Law is an ineffective strategy to reduce uncertainty. We discuss several implications of these weaknesses from both an empirical and a normative perspective. This article is part of the theme issue ‘Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications’.

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