Temporal and effort cost decision-making in healthy individuals with subclinical psychotic symptoms

The value people attribute to rewards is influenced both by the time and the effort required to obtain them. Impairments in these computations are described in patients with schizophrenia and appear associated with negative symptom severity. This study investigated whether deficits in temporal and effort cost computations can be observed in individuals with subclinical psychotic symptoms (PS) to determine if this dysfunction is already present in a potentially pre-psychotic period. Sixty participants, divided into three groups based on the severity of PS (high, medium and low), performed two temporal discounting tasks with food and money and a concurrent schedule task, in which the effort to obtain food increased over time. We observed that in high PS participants the discounting rate appeared linear and flatter than that exhibited by participants with medium and low PS, especially with food. In the concurrent task, compared to those with low PS, participants with high PS exerted tendentially less effort to obtain snacks only when the required effort was high. Participants exerting less effort in the higher effort condition were those with higher negative symptoms. These results suggest that aberrant temporal and effort cost computations might be present in individuals with subclinical PS and therefore could represent a vulnerability marker for psychosis

Hedonics of Food Consumption: Are Food ‘Liking’ and ‘Wanting’ Viable Targets for Appetite Control in the Obese?

In an environment where energy-dense and highly palatable foods are ubiquitous, it seems plausible that the hedonic system of appetite control will play a primary role in eating behavior—undermining homeostatic processes and driving consumption beyond energy requirements. A relevant issue in the hedonics of food consumption is the distinction between “liking” and “wanting” components of food reward. Separate neural pathways exist to mediate these processes, and experimental behavioral methods have been developed to distinguish and to measure them separately in humans. We examine the evidence that “liking” and “wanting” are involved in weight gain, obesity, and certain forms of disordered eating. Then it is questioned whether “liking” and “wanting” are involved in “food addiction.” We conclude that elevated “liking” and “wanting” are psychological markers of a susceptible phenotype for overconsumption. These processes contribute to what can be termed “hedonically driven eating” and represent viable targets for appetite control