Emotions play a key role in overall mental health, [1] and sleep plays a crucial role in maintaining the optimal homeostasis of emotional functioning. [2] [3] Deficient sleep, both in the form of sleep deprivation and restriction, adversely impacts emotion generation, emotion regulation, and emotional expression. [4]
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 intensity [5] (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 intensity [6] (also referred to as Fatigue 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. [5] 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. [7] Pupil diameter was shown to increase significantly in response to negative photographs following sleep deprivation. [8] When exposed to positive stimuli, sleep deprived participants showed amplified emotional reactivity throughout various midbrain, striatal, limbic, and visual processing brain regions. [9] One night of sleep deprivation caused participants to judge neutral images more negatively than non sleep deprived participants. [10] One night of sleep loss also caused increased impulsivity to negative stimuli. [11]
The fatigue-model is supported by subjective self-report and physiological studies. Arousal, as measured by electroencephalograph (EEG), decreases as sleep loss increases, [6] 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. [12] 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, [13] as well as decreased vocal expression of positive emotion. [14] Sleep deprivation slows the generation of facial reactions in response to emotional faces. [15] 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. [16] 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. [17]
Deficient sleep patterns are prominent in many psychiatric ailments. [18] 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. [19] Amongst manic bipolar patients, sleep loss may act as a trigger in the onset of a manic episode. [20]
Sleep patterns are affected by behavioral and emotional disorders, and aspects of emotional and cognitive well-being are influenced by sleep patterns. [21] Scientists have examined the effects of deficient sleep patterns on emotion regulation in individuals diagnosed with mental disorders ( e.g. depression and anxiety), [22] borderline personality disorder, bipolar disorder, [19] and panic disorder. [23] Methods typically include observational, subjective, behavioral, and physiological measures of emotional functioning. [24]
Emotion regulation difficulties are associated with greater symptoms of depression, anxiety, [25] and borderline personality, that worsen with poor sleep patterns. Heart rate variability (HRV) is described as the time interval between heartbeats, and is linked to emotion regulation capacity, [26] with higher resting HRV is associated with greater emotion regulation capacity, and lower resting HRV is associated with low emotion regulation capacity. [27] Physiological data suggests that HRV is negatively affected by sleep loss, [24] as seen in panic disorder patients with poor sleep quality who display increased cognitive inhibition due to reduced HRV. [23] Emotion dysregulation has also been shown to play a role in the maintenance of generalized anxiety disorder, [28] panic disorder, [29] obsessive-compulsive disorder, [30] and posttraumatic stress disorder. [31] Overall deficient sleep plays a role in dampening emotions in clinical populations already susceptible to emotion dysregulation, as well as maintaining various psychiatric conditions through contributing to emotion dysfunction. [32]
Several important emotional characteristics that develop in childhood have been linked to sleep quality and duration, for example approachability, adaptability and attachment. [33] Sleep disruption has been argued to play a role in crying frequency. Crying was interpreted as an early form of a behavioral dysregulation and has therefore been linked to emotion regulation. [34]
It is hypothesized that dreaming might be a way of improving mood in non-clinical populations. [35] The evidence for this phenomenon has been collected from home dream reports in psychotherapy and from laboratory dreams collected after waking a participant in a REM sleep phase. [36] Adults often remember dreams which have a negative emotional component, whereby women recall more dreams than men and dream recall is associated with a higher level of anxiety and lighter sleep. [37]
In a study [38] conducted with depressed and healthy adults and were able to show that in healthy subjects, dreaming was a way to positively influence mood and cope with stress at night. Dreams of depressed persons, however, might deteriorate their mood further. This study's interesting results are limited in generalizability due to the small sample and the lack of reported dreams by depressed patients.
Emotions are more apparent in stages of REM-sleep rather than other stages of sleep. [39] It was found that during REM-sleep negative emotions diminish. [39] After going through stages of REM-sleep, people with depression report feeling better, in a study done by Cartwright et al. [40] Conversely, a theory proposed by Revonsuo [41] states that when people experience negative emotions or negative events, when they sleep the REM-sleep replays such events, which is known as rehearsal. [39] During REM-sleep areas of the brain, the suborbital area, and the cortical area are responsible for emotion but also a suppression of arousing emotions are activated. [39] Scientists noticed a decrease in the hormone noradrenaline which is released into the body after a highly stimulating event. [39] People reported trouble falling asleep or sleeping consistently throughout the night when a stressful event was happening in their life, as observed by Åkerstedt. [42] REM-sleep aids people with negative emotion or high stress. [39]
The circadian rhythm provides a person with a signal for when to sleep and when to wake up. [43] If circadian rhythm and sleep-wake cycle are misaligned, this might lead to negative affect and emotional instability. [44] It has been found that emotions vary depending on the circadian rhythm and the duration of how long one was awake. [45] Circadian sleep-rhythm disorders like shift-work disorder or Jetlag-disorder have been found to similarly contribute to the Dysregulation of affect, with symptoms like irritability, anxiety, apathy and dysphoria. [46]
Sleep is a state of reduced mental and physical activity in which consciousness is altered and sensory activity is inhibited to a certain extent. During sleep, there is a decrease in muscle activity, and interactions with the surrounding environment. While sleep differs from wakefulness in terms of the ability to react to stimuli, it still involves active brain patterns, making it more reactive than a coma or disorders of consciousness.
A sleep disorder, or somnipathy, is a medical disorder of an individual's sleep patterns. Some sleep disorders are severe enough to interfere with normal physical, mental, social and emotional functioning. Sleep disorders are frequent and can have serious consequences on patients’ health and quality of life. Polysomnography and actigraphy are tests commonly ordered for diagnosing sleep disorders.
Rapid eye movement sleep is a unique phase of sleep in mammals and birds, characterized by random rapid movement of the eyes, accompanied by low muscle tone throughout the body, and the propensity of the sleeper to dream vividly.
In psychology, a mood is an affective state. In contrast to emotions or feelings, moods are less specific, less intense and less likely to be provoked or instantiated by a particular stimulus or event. Moods are typically described as having either a positive or negative valence. In other words, people usually talk about being in a good mood or a bad mood. There are many different factors that influence mood, and these can lead to positive or negative effects on mood.
A mood swing is an extreme or sudden change of mood. Such changes can play a positive part in promoting problem solving and in producing flexible forward planning, or be disruptive. When mood swings are severe, they may be categorized as part of a mental illness, such as bipolar disorder, where erratic and disruptive mood swings are a defining feature.
Sleep debt or sleep deficit is the cumulative effect of not getting enough sleep. A large sleep debt may lead to mental or physical fatigue, and can adversely affect one's mood, energy, and ability to think clearly.
Wake therapy is a specific application of intentional sleep deprivation. It encompasses many sleep-restricting paradigms that aim to address mood disorders with a form of non-pharmacological therapy.
Irritability is the excitatory ability that living organisms have to respond to changes in their environment. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessive sensitivity to stimuli.
Reduced affect display, sometimes referred to as emotional blunting or emotional numbing, is a condition of reduced emotional reactivity in an individual. It manifests as a failure to express feelings either verbally or nonverbally, especially when talking about issues that would normally be expected to engage emotions. In this condition, expressive gestures are rare and there is little animation in facial expression or vocal inflection. Additionally, reduced affect can be symptomatic of autism, schizophrenia, depression, post-traumatic stress disorder, depersonalization disorder, schizoid personality disorder or brain damage. It may also be a side effect of certain medications.
Emotional dysregulation is a range of emotional responses that do not lie within a desirable scope of emotive response, considering the stimuli.
In the study of psychology, neuroticism has been considered a fundamental personality trait. In the Big Five approach to personality trait theory, individuals with high scores for neuroticism are more likely than average to be moody and to experience such feelings as anxiety, worry, fear, anger, frustration, envy, jealousy, pessimism, guilt, depressed mood, and loneliness. Such people are thought to respond worse to stressors and are more likely to interpret ordinary situations, such as minor frustrations, as appearing hopelessly difficult. The responses can include maladaptive behaviors, such as dissociation, procrastination, substance use, etc., which aids in relieving the negative emotions and generating positive ones.
Emotional self-regulation or emotion regulation is the ability to respond to the ongoing demands of experience with the range of emotions in a manner that is socially tolerable and sufficiently flexible to permit spontaneous reactions as well as the ability to delay spontaneous reactions as needed. It can also be defined as extrinsic and intrinsic processes responsible for monitoring, evaluating, and modifying emotional reactions. Emotional self-regulation belongs to the broader set of emotion regulation processes, which includes both the regulation of one's own feelings and the regulation of other people's feelings.
Sleep deprivation, also known as sleep insufficiency or sleeplessness, is the condition of not having adequate duration and/or quality of sleep to support decent alertness, performance, and health. It can be either chronic or acute and may vary widely in severity. All known animals sleep or exhibit some form of sleep behavior, and the importance of sleep is self-evident for humans, as nearly a third of a person's life is spent sleeping.
Emotional responsivity is the ability to acknowledge an affective stimuli by exhibiting emotion. It is a sharp change of emotion according to a person's emotional state. Increased emotional responsivity refers to demonstrating more response to a stimulus. Reduced emotional responsivity refers to demonstrating less response to a stimulus. Any response exhibited after exposure to the stimulus, whether it is appropriate or not, would be considered as an emotional response. Although emotional responsivity applies to nonclinical populations, it is more typically associated with individuals with schizophrenia and autism.
Scientific studies have found that different brain areas show altered activity in humans with major depressive disorder (MDD), and this has encouraged advocates of various theories that seek to identify a biochemical origin of the disease, as opposed to theories that emphasize psychological or situational causes. Factors spanning these causative groups include nutritional deficiencies in magnesium, vitamin D, and tryptophan with situational origin but biological impact. Several theories concerning the biologically based cause of depression have been suggested over the years, including theories revolving around monoamine neurotransmitters, neuroplasticity, neurogenesis, inflammation and the circadian rhythm. Physical illnesses, including hypothyroidism and mitochondrial disease, can also trigger depressive symptoms.
The neuroscience of sleep is the study of the neuroscientific and physiological basis of the nature of sleep and its functions. Traditionally, sleep has been studied as part of psychology and medicine. The study of sleep from a neuroscience perspective grew to prominence with advances in technology and the proliferation of neuroscience research from the second half of the twentieth century.
Sleep disorder is a common repercussion of traumatic brain injury (TBI). It occurs in 30%-70% of patients with TBI. TBI can be distinguished into two categories, primary and secondary damage. Primary damage includes injuries of white matter, focal contusion, cerebral edema and hematomas, mostly occurring at the moment of the trauma. Secondary damage involves the damage of neurotransmitter release, inflammatory responses, mitochondrial dysfunctions and gene activation, occurring minutes to days following the trauma. Patients with sleeping disorders following TBI specifically develop insomnia, sleep apnea, narcolepsy, periodic limb movement disorder and hypersomnia. Furthermore, circadian sleep-wake disorders can occur after TBI.
Sleep is a naturally recurring state of mind and body, characterized by altered consciousness, relatively inhibited sensory activity, reduced muscle activity, and inhibition of nearly all voluntary muscles during rapid eye movement (REM) sleep, and reduced interactions with surroundings. An essential aspect of sleep is that it provides the human body with a period of reduced functioning that allows for the systems throughout the body to be repaired. This time allows for the body to recharge and return to a phase of optimal functioning. It is recommended that adults get 7 to 9 hours of sleep each night. Sleep is regulated by an internal process known as the circadian rhythm. This 24-hour cycle regulates periods of alertness and tiredness that an individual experiences. The correlation between psychological stress and sleep is complex and not fully understood. In fact, many studies have found a bidirectional relationship between stress and sleep. This means that sleep quality can affect stress levels, and stress levels can affect sleep quality. Sleep change depends on the type of stressor, sleep perception, related psychiatric conditions, environmental factors, and physiological limits.
Sleep is known to play an important role in the etiology and maintenance of bipolar disorder. Patients with bipolar disorder often have a less stable and more variable circadian activity. Circadian activity disruption can be apparent even if the person concerned is not currently ill.
Affect labeling is an implicit emotional regulation strategy that can be simply described as "putting feelings into words". Specifically, it refers to the idea that explicitly labeling one's, typically negative, emotional state results in a reduction of the conscious experience, physiological response, and/or behavior resulting from that emotional state. For example, writing about a negative experience in one's journal may improve one's mood. Some other examples of affect labeling include discussing one's feelings with a therapist, complaining to friends about a negative experience, posting one's feelings on social media or acknowledging the scary aspects of a situation.