Objectives: To investigate decision-making and addictive behaviors in narcolepsy-cataplexy (NC). NC is caused by the loss of hypothalamic neurons that produce hypocretins. The hypocretin system plays a crucial role in sleep, wakefulness, and energy homeostasis, and is also involved in emotion regulation, reward processing, and addiction.
Setting: Academic sleep center.
Patients: 23 subject with NC and 23 matched healthy controls.
Design: We used the Iowa Gambling Task (IGT) to assess decision making under ambiguity condition based on emotional feedback processing and the Game of Dice Task (GDT) to assess decision making under risk condition. All participants underwent a semi-structured psychiatric interview and completed the Beck Depression Inventory-II and the UPPS Impulsive Behavior Scale. Patients underwent one night of polysomnography followed by an MSLT, with neuropsychological evaluation performed between MSLT sessions.
Measurements and results: NC patients had higher depressive symptoms and showed a significant lack of perseverance. One NC patient had a past history of drug dependence. NC patients also exhibited selective reduced IGT performance and normal performance on the GDT. No clinical or polysomnographic characteristics were associated with increased sensitivity to reward and/or decreased sensitivity to punishment. However, lack of perseverance in NC patients was associated with disadvantageous decision making on the IGT.
Conclusion: We demonstrated a lack of perseverance and a selective reduced performance on decision making under ambiguity in NC in contrast to normal decision making under explicit conditions. Patients with narcolepsy-cataplexy may opt for choices with higher immediate emotional valence, regardless of higher future punishment, to compensate for their reduced reactivity to emotional stimuli.
Keywords: Game of Dice Task; Iowa Gambling Task; Narcolepsy with cataplexy; hypocretin/orexin system; reward processing.