Emotions play a key role in overall mental health,Goldstein, A. N., & Walker, M. P. (2014). The Role of Sleep in Emotional Brain Function. Annual Review of Clinical Psychology, 10(1), 679-708. and sleep plays a crucial role in maintaining the optimal homeostasis of emotional functioning.Dahl, R. E. (1996). The regulation of sleep and arousal: Development and psychopathology. Development and Psychopathology, 8(01), 3. Gujar, N., Yoo, S., Hu, P., & Walker, M. P. (2011). Sleep deprivation amplifies reactivity of brain reward networks, biasing the appraisal of positive emotional experiences. Journal of Neuroscience, 31(12), 4466-4474. Deficient sleep, both in the form of sleep deprivation and restriction, adversely impacts emotion generation, emotion regulation, and emotional expression.Palmer, C. A., & Alfano, C. A. (2016). Sleep and emotion regulation: An organizing, integrative review. Sleep Medicine Reviews. People who fail to get enough sleep have a harder time controlling their emotions. Stress tolerance, patience and emotional reactivity are all negatively impacted by not enough or poor sleep. On the other hand having persistent stress and emotional distress can make it difficult to fall or stay asleep, which feeds back into a cycle of poor mood and lack of sleep.
Models of sleep loss and emotional reactivity Scientists offer two explanations for the effects of sleep loss on emotions. One explanation is that sleep loss causes disinhibition of emotional brain regions, leading to an overall increase in emotional intensityYoo, S., Gujar, N., Hu, P., Jolesz, F. A., & Walker, M. P. (2007). The human emotional brain without sleep — a prefrontal amygdala disconnect. Current Biology, 17(20). (also referred to as Dysregulation Model). The other explanation describes how sleep loss causes an increase in fatigue and sleepiness, coupled with an overall decrease in energy and arousal, leading to an overall decrease in emotional intensityEngle-Friedman, M. (2014). The effects of sleep loss on capacity and effort. Sleep Science, 7(4),213-224. (also referred to as Fatigue Model).
Neurobiological Mechanisms Neurobiological evidence supports the connection between sleep and emotional regulation. REM (rapid eye movement) sleep, particularly helps the processing and incorporation of emotional memories by controlling neural activity in the amygdala, hippocampus, and prefrontal cortex. In a neurochemical setting that encourages memory consolidation and lessens the emotional intensity associated with those memories, the brain reactivates emotional experiences during REM sleep. Lack of sleep disrupts this process and had been linked to decreased functional connectivity between the amygdala and the prefrontal cortex, which controls emotions, as well as heightened amygdala activation in response to negative stimuli. Overactive emotional reactions, irritability and trouble managing stress are all influenced by this hyperactive and disconnected pattern.
The dysregulation model The dysregulation model is supported by neuroanatomical, physiological, and subjective self-report studies. Emotional brain regions (e.g. the amygdala) have shown 60% greater reactivity to emotionally negative photographs following one night of sleep deprivation, as measured by functional magnetic resonance imaging. Five days of sleep restriction (four hour sleep opportunity per night) caused a decrease in connectivity with cortical brain regions involved in the regulation of the amygdala.Motomura, Y., Kitamura, S., Oba, K., Terasawa, Y., Enomoto, M., Katayose, Y., & Mishima, K. (2013). Sleep Debt Elicits Negative Emotional Reaction through Diminished Amygdala-Anterior Cingulate Functional Connectivity. PLOS ONE, 8(2). Pupil diameter was shown to increase significantly in response to negative photographs following sleep deprivation.Franzen, P. L., Buysse, D. J., Dahl, R. E., Thompson, W., & Siegle, G. J. (2009). Sleep deprivation alters pupillary reactivity to emotional stimuli in healthy young adults. Biological Psychology, 80(3), 300-305. When exposed to positive stimuli, sleep deprived participants showed amplified emotional reactivity throughout various midbrain, striatal, limbic, and visual processing brain regions.Gujar, N., Yoo, S., Hu, P., & Walker, M. P. (2011). Sleep Deprivation Amplifies Reactivity of Brain Reward Networks, Biasing the Appraisal of Positive Emotional Experiences. Journal of Neuroscience, 31(12), 4466-4474. One night of sleep deprivation caused participants to judge neutral images more negatively than non sleep deprived participants.Tempesta, D., Couyoumdjian, A., Curcio, G., Moroni, F., Marzano, C., & Ferrara, M. (2010). Lack of sleep affects the evaluation of emotional stimuli. Brain Research Bulletin, 82(1-2), 104-108. One night of sleep loss also caused increased impulsivity to negative stimuli.Anderson, C., & Platten, C. R. (2011). Sleep deprivation lowers inhibition and enhances impulsivity to negative stimuli. Behavioural Brain Research, 217(2), 463-466.
The fatigue model
The fatigue-model is supported by subjective self-report and physiological studies. Arousal, as measured by electroencephalograph (EEG), decreases as sleep loss increases, leading to a decrease in the desire to perform and exert effort. Short-term sleep loss is associated with blunting in the recognition of negative and positive facial expressions.Van der Helm, E., Gujar, N., & Walker, M. (2010). Sleep Deprivation Impairs the Accurate Recognition of Human Emotions. Sleep, 33(3). Various forms of emotional expression, including facial and vocal expression, are adversely affected by sleep loss. Following one night of sleep deprivation, participants show decreased facial expressiveness in response to positive stimuli,Minkel, J., Htaik, O., Banks, S., & Dinges, D. (2011). Emotional expressiveness in sleep-deprived healthy adults. Behavioral Sleep Medicine, 9(1), 5-14. as well as decreased vocal expression of positive emotion.McGlinchey, E., Talbot, L., Chang, K., Kaplan, K., Dahl, R., & Harvey, A. (2011). The Effect of Sleep Deprivation on Vocal Expression of Emotion in Adolescents and Adults. Sleep, 35(9). Sleep deprivation slows the generation of facial reactions in response to emotional faces.Schwarz, J. F., Popp, R., Haas, J., Zulley, J., Geisler, P., Alpers, G. W., & Eisenbarth, H. (2013). Shortened night sleep impairs facial responsiveness to emotional stimuli. Biological Psychology, 93(1), 41-44. One to two nights of sleep loss in healthy adults is associated with a decrease in the generated intensity of positive moods (i.e. happiness and activation), as well as an increase in the generated intensity of negative moods (i.e. anger, depression, fear, and fatigue). Long-term chronic exposure to insufficient sleep is associated with a decline in optimism and sociability, and an increase in subjective experiences of sleepiness and fatigue.Haack, M., & Mullington, J. M. (2005). Sustained sleep restriction reduces emotional and physical well-being. Pain, 119(1-3), 56-64. Furthermore, sleep restricted to five hours a night over the course of a week causes significant increases in self-reports of subjective mood disturbance and sleepiness.Dinges, D. F. (1995). An overview of sleepiness and accidents. Journal of Sleep Research, 4, 4-14.
Sleep, emotions, and psychiatric ailments Deficient sleep patterns are prominent in many psychiatric ailments.Benca, R. M. (1992). Sleep and Psychiatric Disorders. Archives of General Psychiatry, 49(8), 651. Insomnia increases the risk of a depressive episode, sleep deprivation influences the onset of hypomania, and sleep disturbance contributes to the maintenance of mood disorders.Harvey, A. G. (2011). Sleep and Circadian Functioning: Critical Mechanisms in the Mood Disorders? Annual Review of Clinical Psychology, 7(1), 297-319. Amongst manic bipolar patients, sleep loss may act as a trigger in the onset of a manic episode.Barbini, B., Bertelli, S., Colombo, C., & Smeraldi, E. (1996). Sleep loss, a possible factor in augmenting manic episode. Psychiatry Research, 65(2), 121-125.
Sleep patterns are affected by behavioral and emotional disorders, and aspects of emotional and cognitive well-being are influenced by sleep patterns.Dahl, R. E., & Lewin, D. S. (2002). Pathways to adolescent health sleep regulation and behavior. Journal of Adolescent Health, 31(6), 175-184. Scientists have examined the effects of deficient sleep patterns on emotion regulation in individuals diagnosed with mental disorders ( e.g. depression and anxiety),Markarian, S. A., Pickett, S. M., Deveson, D. F., & Kanona, B. B. (2013). A model of BIS/BAS sensitivity, emotion regulation difficulties, and depression, anxiety, and stress symptoms in relation to sleep quality. Psychiatry Research, 210, 281-286. borderline personality disorder, bipolar disorder, and panic disorder.Hovland, A., Pallesen, S., Hammar, Å, Hansen, A. L., Thayer, J. F., Sivertsen, B., . . . Nordhus, I. H. (2013). Subjective sleep quality in relation to inhibition and heart rate variability in patients with panic disorder. Journal of Affective Disorders, 150(1), 152-155. Techniques like cognitive reappraisal (reframing negative events in a less distressing light) depend on sufficient sleep. When sleep is restricted, people and to rely more on maladaptive strategies such as suppression or rumination, which heighten emotional distress and increase vulnerability to anxiety and depression. Other methods typically include observational, subjective, behavioral, and physiological measures of emotional functioning.Gruber, R., & Cassoff, J. (2014). The interplay between sleep and emotion regulation: conceptual framework empirical evidence and future directions. Current Psychiatry Reports, 16(11).