Delay of gratification in narcolepsy

Orexins are involved in the regulation of food intake and sleep. Narcolepsy is characterized by a central orexin deficiency. Studies report an increased body weight in narcolepsy. The inability to delay gratification is related to obesity. This study investigates the delay of gratification in patients with narcolepsy. Nine patients with verified narcolepsy (F/M 7/2: age 37.9 ± 18y; BMI 25.0 ± 4.9 kg/m²) were included. We designed a board game to assess the delay of gratification. On designated fields patients had to decide whether they choose an immediate gratification consisting of a sweetie or whether they get double of the amount in the end of the game. The sleepiness was assed with the Karolinska Sleepiness Scale (KSS) before and after the game. Nine control subjects were individually matched for gender, age and BMI (age: 38 ± 18 y; BMI 25.3 ± 4.8 kg/m²). The percentage of decisions in favor of delaying did not differ significantly between narcoleptic patients (89 ± 10%) and controls (83 ± 19%, p = 0.41). The percentage of decisions in favor of the delay increased little in the narcoleptic group (80, 91, 93%) across the three thirds. It showed a steep increase in the control group (65, 86, 92%). KSS dropped or remained stable in all but one narcoleptic individuals. These preliminary results suggest no obvious peculiarities concerning the delay of gratification in narcolepsy. The board game emerged as valuable tool that takes into account the sleepiness of narcoleptic patients.