Assessment of intertemporal preferences in Type-2 Diabetes patients and smokers

Abstract

The experiment assesses the role of cortisol concentration on bloodstream as correlate of the intertemporal choice and temporal discrimination in Type-2 Diabetes Mellitus (T2DM) patients and smokers. The participants were evaluated in a two independent computerized tasks allowed to obtain the temporal discount function and it's hyperbolic decay parameter (k), which refers to the tendency to discount the subjective value of future goods as a function of the delay to receiving them; and a temporal discrimination index (bisection point), this function relate the response proportion of "Long" stimuli with probe duration. The bisection point is the value at which responses to Short and Long stimuli occur with equal frequency. We analysed both parameters, then a comparisons of the temporal discount parameter [F(2;147) = 79:858; p lt;01] and time discrimination parameter [F(2,147) = 49,51; p lt;01] revealed statistically significant differences between control group and T2DM and smokers groups. We concluded that the choice for delayed rewards and the temporal discrimination of T2DM patients and smokers were influenced by the cortisol concentration in the bloodstream; the higher the concentration of cortisol in the bloodstream, the higher the likelihood to choose immediate rewards over larger delayed rewards and the higher the tendency to overestimate the passage of time. We propose to investigate the effects of salivary cortisol elevation levels through noninvasive pharmacologically induction on healthy adult humans, to extend the research line that assess the direct influence over intertemporal choice and temporal discrimination to increase the effect generality.