Sleep and mental health

While many people believe that the duration of sleep positively correlates to sleep quality, this statement, while true, does not paint the full picture. Sleep is multidimensional by nature, so poor sleep can result from a combination of factors, including an insufficient duration of sleep, multiple sleep disturbances, improper timing, or a poor quality of sleep overall. Multiple studies have proven that poor sleep quality and poor mental health have a bidirectional relationship. With this framework in mind, sleep is fundamental to health as it influences brain function, metabolic regulation, and the immune and cardiovascular systems, among other functions for the body. Psychologically, it directly affects affective functioning, or how someone regulates their mood and emotions.

An area of the brain called the prefrontal cortex controls the amygdala, a part of the brain responsible for emotional regulation. When sleep deprivation occurs, it disrupts the neural connections between these areas in the brain, leading to the amygdala becoming hyperactive. As a result, people with sleep deprivation have exaggerated emotional responses, mostly when they respond to negative stimuli. They have more mood swings, become irritable, and respond negatively to minor stressors. Sleep deprived people are also likely to experience a negativity bias. For example, they may show a disruption in facial emotion recognition, making it difficult for them to distinguish between different facial expressions. Thus, individuals have trouble maintaining social interactions, which can lead to social withdrawal. In combination, effects like these from sleep deprivation can lead to depression, anxiety, and even bipolar disorder.

Those who already have chronic sleep disorders are also more likely to develop mental health disorders. Studies using neuroimaging have found this relationship in those with primary insomnia, which is characterized by immense difficulty falling or staying asleep. For example, Hyndych et. al. (2025) found that those with primary insomnia showed a decreased connectivity between the sensorimotor networks, default mode network, and striatum of the brain. When there is less coordination among these systems in the brain, it becomes difficult to emotionally process stimuli and rewards. It was also found that 40% of those who suffer from insomnia also have a mental health disorder that is severe enough to be diagnosed, the most common being major depressive disorder. Overall, there can be short-term and long-term consequences of both acute and chronic sleep deprivation, which vary among individuals. Poor sleep does not guarantee the development of mental health disorders, but makes them more likely to occur.