How sleep deprivation impacts emotional health and cognitive abilities

Sleep deprivation can affect both emotional regulation and cognitive performance:

• Amplifies emotional reactions: Even relatively mild restriction—under six hours a night for five nights—was linked to heightened emotional reactivity. Sleep-deprived people reacted more strongly to negative stimuli, and situations that normally felt neutral could become upsetting. The medial prefrontal cortex’s regulatory connection to the amygdala was weakened, making emotions harder to control. 1 2
• Makes mood less steady and motivation lower: People may become irritable, snap more easily, or swing between unusually strong reactions to negative and rewarding events. Sleep loss can also reduce motivation to socialize, learn, or exert effort, while increasing impulsivity and reward-seeking. 3 4
• Impairs judgment and decision-making: Sleep loss can reduce the frontal brain regions’ ability to regulate emotional and reward centers; in one food-choice study, participants rated less healthy foods as more desirable when sleep-deprived. 5
• Can disrupt thinking more severely when prolonged: In the discussion of prolonged sleep deprivation, hallucinations and delusions appeared by day five, with participants approaching severe psychosis. 6

In short, too little sleep can make emotions more reactive while weakening the brain systems that help regulate feelings, choices, and behavior.