Constraint theory: A cognitive, motivational theory of dependence

Aims: A new theory of substance dependence is presented that models dependence as the absence of cognitive constraints on substance use. Methods: (1) Critical review of the predominant paradigm that assumes that substance dependence is a pathological state fundamentally caused by the neuropsychopharmacological effects of drugs (NPP paradigm) identified four counter-factual assumptions. Contrary to the NPP paradigm: (I) dependence can occur on a-typical substances and other things; (II) dependence is a complex, gradated phenomenon, not a state; (III) heavy protracted substance use can occur without dependence; and (IV) NPP interventions against dependence have not worked other than as drug substitutes. (2) Reconceptualisation of dependence as substance use with few cognitive, behavioural or social constraints. (3) Development of an exhaustive list of constraints on substance use with a panel of experts, achieving theoretical saturation. (4) Modelling of dependence, specifically to explain why socioeconomic deprivation is correlated with substance dependence. Results: Fifteen common constraints are described, which prevent most substance users becoming dependent. People in more socioeconomically deprived conditions tend to have fewer constraints. Similarities between Constraint Theory and previous sociological and social cognitive theories are discussed. Conclusions: Constraint theory describes the known nature of substance dependence better than theories from the NPP paradigm. Conceptualising dependence as an absence of constraints shows promise as a theory of addiction and fits with existing knowledge about what works to prevent and treat substance dependence

How to measure mood in nutrition research

© 2014 The Authors. Mood is widely assessed in nutrition research, usually with rating scales. A core assumption is that positive mood reinforces ingestion, so it is important to measure mood well. Four relevant theoretical issues are reviewed: (i) the distinction between protracted and transient mood; (ii) the distinction between mood and emotion; (iii) the phenomenology of mood as an unstable tint to consciousness rather than a distinct state of consciousness; (iv) moods can be caused by social and cognitive processes as well as physiological ones. Consequently, mood is difficult to measure and mood rating is easily influenced by non-nutritive aspects of feeding, the psychological, social and physical environment where feeding occurs, and the nature of the rating system employed. Some of the difficulties are illustrated by reviewing experiments looking at the impact of food on mood. The mood-rating systems in common use in nutrition research are then reviewed, the requirements of a better mood-rating system are described, and guidelines are provided for a considered choice of mood-rating system including that assessment should: have two main dimensions; be brief; balance simplicity and comprehensiveness; be easy to use repeatedly. Also mood should be assessed only under conditions where cognitive biases have been considered and controlled

Food choice by people with intellectual disabilities at day centres: A qualitative study

People with intellectual disabilities experience a range of health inequalities. It is important to investigate possible contributory factors that may lead to these inequalities. This qualitative study identified some difficulties for healthy eating in day centres. (1) Service users and their family carers were aware of healthy food choices but framed these as diets for weight loss rather than as everyday eating. (2) Paid carers and managers regarded the principle of service user autonomy and choice as paramount, which meant that they felt limited in their capacity to influence food choices, which they attributed to the home environment. (3) Carers used food as a treat, a reward and for social bonding with service users. (4) Service users’ food choices modelled other service users’ and carers’ choices at the time. It is suggested that healthy eating should be made more of a priority in day care, with a view to promoting exemplarily behaviour that might influence food choice at home

Testing the Constraint Theory of Addiction: Cannabis Constraints Discriminate Users from Nonusers and Heavy from Light Users

Constraint theory (Hammersley, 2014) offers a novel way of understanding addiction as a lack of cognitive, behavioural, and social constraints on substance use. Here, cannabis constraints were studied in a large online opportunity sample: N = 302; 205 men, 97 women. Age ranged from 14 to 60 years (mean = 25, SD = 8.0). Most participants were from UK or North America. Participants completed a questionnaire assessing 15 cannabis constraints and standard self-report frequency measures of drug use. Factor analysis of the constraint questionnaire found 15 factors, similar to those proposed theoretically. These factors could discriminate well between past and current users and heavy and light users. The best discriminator was concerns about the possibility of becoming addicted; the less concerned the heavier was use, although those who actually felt addicted were more concerned than others. Past users also constrained due to using legal highs instead, concerns about illegality, and using only when others used. Light users constrained due to availability and cost issues, as well as unpleasant effects. These findings suggest that there is utility in constraint theory and that heavy use occurs due to a relative lack of constraints

Schizotypy but not Cannabis Use Modestly Predicts Psychotogenic Experiences: A Cross-Sectional Study Using the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE)

Objective. Cannabis use predicts psychosis in longitudinal studies, but it is difficult to infer causation. Some precursor variables predict both, including childhood trauma and adversity. Additionally, some of the desired effects of cannabis use resemble the symptoms of psychosis. It would be preferable to assess psychotomimetic or “unusual” experiences that include psychotic symptoms but without assuming pathology. Finally, it is possible that similar people are prone to psychosis and drawn to cannabis use, perhaps, because they are sensitive or attracted to unusual experiences. Schizotypy provides a trait measure of proneness to unusual experiences. The study aimed to examine cross-sectionally relationships between cannabis use, schizotypy, and unusual experiences whilst controlling for current trauma symptoms. Method. A volunteer online sample (n = 129, 64% women, predominantly students) who had used cannabis at least once was recruited. People who reported active effects of past trauma were excluded with a brief primary care posttraumatic stress disorder screen. Participants completed the Oxford-Liverpool Inventory of Feelings and Experience, the Cognitive Failures Questionnaire, and measures of substance use and sociodemographics. Results. The majority of respondents recounted unusual experiences after cannabis use, and many of these might have been considered symptoms of psychosis if they had received medical attention. In regression analysis, the only predictor of the unusual experiences scale of O-LIFE was schizotypy (measured by the remaining subscales; 4% of variance). There were no correlations between cannabis use frequency and schizotypy or unusual experiences. Conclusions. These findings suggest that, after controlling for schizotypy and excluding people who are actively experiencing the effects of past trauma, frequency of cannabis use does not predict unusual experiences. However, individuals with schizotypal personality traits may have more unusual experiences when using cannabis

Effects on obese women of the sugar sucrose added to the diet over 28 d: a quasi-randomised, single-blind, controlled trial

To investigate whether obese women can compensate for sucrose added to the diet when it is given blind, rather than gaining weight or exhibiting dysfunctional regulation of intake, in the present study, forty-one healthy obese (BMI 30–35 kg/m2) women (age 20–50 years), not currently dieting, were randomly assigned to consume sucrose (n 20) or aspartame (n 21) drinks over 4 weeks in a parallel single-blind design. Over the 4 weeks, one group consumed 4 × 250 ml sucrose drinks (total 1800 kJ/d) and the other group consumed 4 × 250 ml aspartame drinks. During the baseline week and experimental weeks, body weight and other biometric data were measured and steps per day, food intake using 7 d unweighed food diaries, and mood using ten- or seven-point Likert scales four times a day were recorded. At the end of the experiment, the participants weighed 1·72 (se 0·47) kg less than the value predicted by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) model; the predicted body weight accounted for 94·3 % of the variance in the observed body weight and experimental group accounted for a further 1·1 % of the variance in the observed body weight, showing that women consuming sucrose drinks gained significantly less weight than predicted. The reported daily energy intake did not increase significantly, and sucrose supplements significantly reduced the reported voluntary sugar, starch and fat intake compared with aspartame. There were no effects on appetite or mood. Over 4 weeks, as part of everyday eating, sucrose given blind in soft drinks was partially compensated for by obese women, as in previous experiments with healthy and overweight participants

Cost accounting at Keswick, England, c. 1598-1615: The German connection

The growing literature on the history of cost and management accounting has left virtually unexplored the developments prior to the British industrial revolution. Recently the business notebooks of Daniel Hechstetter, the German manager of an English copper works from 1597 to 1633, have been transcribed and published, making available what is probably the most detailed set of business records for a British-based industrial enterprise in this period. This paper examines Hechstetter\u27s background and role at Keswick, and translates a sample of the calculations into modern English. These calculations show that a number of modern cost accounting concepts and procedures were in use by c. 1600. The significance of this in relation to our understanding of the development of cost and management accounting is assessed, and it is shown that there is a strong case for claiming that German enterpreneurs involved in this enterprise were responsible for introducing a range of cost accounting techniques to Britain

Stuffing down feelings: Bereavement, anxiety and emotional detachment in the life stories of people with eating disorders

This study aimed to explore the life stories of people with eating disorders (EDs) in order to better understand possible contributing factors to their development. It used a qualitative Life Story method, in order to reduce the tendency to focus on the negative in the lives of people with EDs. Sixteen people in contact with an EDs charity participated. Data were analysed using a thematic analysis. Despite the attempt to elicit both positive and negative information, most themes from the life stories were negative. Here, the focus is on the three most common themes reported, which are less often reported in previous research: (a) substantial bereavement and loss; (b) major issues with anxiety and (c) difficulties coping with emotions. A model is proposed whereby major losses and the resultant anxiety can lead to emotional deadening and ‘stuffing down feelings’ with food, leading on to an ED. This model implies that interventions need to consider psychological factors in an ED, especially the use of it as a dysfunctional coping strategy, as well as the behavioural and physiological aspects of an ED

On the McKean-Vlasov dynamics with or without common noise

McKean-Vlasov stochastic differential equations may arise from a probabilistic interpretation of certain non-linear PDEs or as the limiting behaviour of mean field particle systems (those whose interactions are through the empirical measure) as the population size increases to infinity. Interest in this topic has grown enormously in recent times following the introduction of the related mean field games. These are models derived from the infinite population limit of games with finitely many players and mean field structure, i.e. the dynamics and rewards of one player depend on the other players through the empirical measure. Naturally, it is imperative that the dynamics of the models are well-posed. This question comprises the majority of this text in two stochastic contexts: with or without a common noise. In the more often studied case where the particles are driven by independent Brownian motions, results are provided that pertain to the weak-existence and pathwise continuous dependence on the initial condition. These results adapt a method of Gyöngy and Krylov for Itô's stochastic differential equations to the McKean-Vlasov setting. Should the coefficients and initial distribution satisfy a certain Lyapunov condition, well-posedness of the dynamics may be established along with the existence of an invariant measure for an associated semi-group. These conditions allow for potentially unbounded coefficients, with growth intrinsically linked to the Lyapunov condition. In the second context, particle systems driven by correlated noises are considered. In particular, the particles are each driven by two Brownian motions: one common to all particles and a private Brownian motion independent of all others. The connection between these particle systems and related McKean-Vlasov models through the conditional propagation of chaos is discussed. Existence and uniqueness of weak solutions to the corresponding McKean-Vlasov dynamics is proved in a particular framework that allows for a discontinuous drift coefficient at a price of non-degenerate noise