Parasomnias

Introduction

Parasomnias are a group of sleep disorders characterized by abnormal behavioral, experiential, or physiological events that occur during sleep or during transitions between sleep and wakefulness. According to the DSM-5-TR, these disturbances may arise during non-rapid eye movement (NREM) sleep, rapid eye movement (REM) sleep, or during partial arousals from sleep.

Parasomnias often involve complex behaviors such as walking, talking, or emotional reactions during sleep, and they may result in distress, impaired functioning, or risk of injury. The major parasomnias include Non-REM Sleep Arousal Disorders (sleepwalking and sleep terrors), Nightmare Disorder, REM Sleep Behavior Disorder, and Restless Legs Syndrome.

Non-REM Sleep Arousal Disorders

Diagnostic Features

Non-REM Sleep Arousal Disorders involve repeated episodes of incomplete awakening from sleep, usually occurring during the first third of the night. Individuals are often unresponsive during the episode and have little or no memory of the event afterward. Two main forms are recognized: sleepwalking and sleep terrors.

DSM-5-TR Diagnostic Criteria

A. Recurrent episodes of incomplete awakening from sleep, usually occurring during the first third of the major sleep episode, accompanied by either sleepwalking or sleep terrors.

B. No or little dream imagery is recalled.

C. Amnesia for the episodes is present.

D. The episodes cause clinically significant distress or impairment.

E. The disturbance is not attributable to substances or another medical condition.

Specify if

Specify if: sleepwalking type.

Specify if: sleep terror type.

Etiology / Causes

Biological Factors:
These disorders are associated with incomplete transitions between deep NREM sleep and wakefulness, particularly during slow-wave sleep. Genetic predisposition plays a significant role, with higher prevalence observed in individuals with a family history of parasomnias. Neurophysiological immaturity in arousal systems, especially in children, contributes to partial awakenings in which motor systems are activated while consciousness remains impaired.

Environmental Factors:
Sleep deprivation, irregular sleep schedules, stress, fever, and certain medications can precipitate episodes by increasing the likelihood of partial arousals. External stimuli such as noise or touch may also trigger episodes in susceptible individuals. Psychological stress and anxiety can further destabilize sleep architecture, increasing vulnerability.

Risk and Prognostic Factors

Risk Factors:
Risk factors include childhood onset, family history of parasomnias, sleep deprivation, and stress. Conditions such as fever, obstructive sleep apnea, and use of sedative medications may also increase the likelihood of episodes.

Prognosis:
Prognosis is generally good, especially in children, as many outgrow the condition with maturation of the nervous system. In adults, persistence may occur but is often manageable with behavioral interventions and lifestyle modifications.

Treatment

Treatment focuses on ensuring safety and improving sleep patterns. Maintaining regular sleep schedules and reducing stress are important.

Behavioral Interventions:
Behavioral strategies include improving sleep hygiene, ensuring adequate sleep duration, and minimizing triggers such as stress and irregular routines. Scheduled awakenings before typical episode times may help prevent occurrences.

Medical and Safety Management:
Environmental safety measures, such as securing doors and removing dangerous objects, are essential. In severe or persistent cases, medications such as benzodiazepines may be considered to reduce arousal frequency.

Sleepwalking Type

Treatment

Treatment focuses on preventing injury and maintaining regular sleep routines.

Safety and Behavioral Management:
Environmental safety measures, including locking doors, using alarms, and removing obstacles, are crucial to prevent injury. Establishing consistent sleep schedules and reducing sleep deprivation significantly decreases episode frequency.

Clinical Interventions:
In frequent or dangerous cases, behavioral techniques such as scheduled awakenings may be used. Pharmacological treatment may be considered in severe cases, although it is generally not first-line.

Sleep Terror Type

Diagnostic Features

Sleep terrors involve sudden arousal from sleep with intense fear, screaming, and autonomic activation such as rapid heart rate. The individual is difficult to console and has little recall of the event.

Treatment

Treatment involves reassurance, stress reduction, and maintaining consistent sleep patterns.

Behavioral and Supportive Approaches:
Providing reassurance to caregivers and reducing stressors in the individual’s environment are key. Maintaining a consistent sleep schedule and ensuring adequate rest can reduce episodes.

Clinical Management:
In severe or persistent cases, behavioral interventions such as scheduled awakenings may be helpful. Medication may be considered if episodes are frequent and cause significant impairment.

Nightmare Disorder

Diagnostic Features

Nightmare Disorder involves repeated occurrences of extended, extremely dysphoric, and well-remembered dreams that usually involve threats to survival or security. Individuals awaken quickly and are alert, often recalling the dream in detail.

DSM-5-TR Diagnostic Criteria

A. Repeated occurrences of extended, extremely dysphoric, and well-remembered dreams.

B. On awakening, the individual rapidly becomes oriented and alert.

C. The disturbance causes clinically significant distress or impairment.

D. The symptoms are not attributable to substances or another medical condition.

Etiology / Causes

Psychological Factors:
Nightmares are often associated with stress, trauma, and anxiety, particularly in individuals with conditions such as post-traumatic stress disorder. Emotional conflicts and heightened arousal levels during sleep can increase the frequency of distressing dreams.

Biological and External Factors:
Sleep deprivation, irregular sleep schedules, and certain medications (such as antidepressants or beta-blockers) can contribute to nightmare occurrence. Increased REM sleep density and heightened brain activity during dreaming are also implicated.

Risk and Prognostic Factors

Risk Factors:
Risk factors include trauma exposure, anxiety disorders, stress, and disrupted sleep patterns. Children are more likely to experience nightmares, though they often decrease with age.

Prognosis:
The prognosis is generally good, especially when underlying stressors are addressed. Chronic nightmares may persist in individuals with ongoing psychological conditions.

Treatment

Treatment focuses on reducing distress and improving sleep quality.

Psychological Interventions:
Cognitive-behavioral therapy (CBT) and imagery rehearsal therapy (IRT) are commonly used to modify the content of nightmares and reduce their frequency. Relaxation techniques and stress management are also effective.

Supportive Measures:
Improving sleep hygiene and addressing underlying psychological conditions are essential. In severe cases, medications may be used to reduce nightmare frequency.

REM Sleep Behavior Disorder

Diagnostic Features

REM Sleep Behavior Disorder involves repeated episodes of arousal during sleep associated with vocalization and complex motor behaviors. These behaviors often correspond to dream enactment.

DSM-5-TR Diagnostic Criteria

A. Repeated episodes of arousal during sleep associated with vocalization and/or complex motor behaviors.

B. These behaviors arise during REM sleep and are often associated with dream enactment.

C. Upon awakening, the individual is alert and oriented.

D. The disturbance causes clinically significant distress or injury.

E. The disturbance is not attributable to substances or another condition.

Etiology / Causes

Biological Factors:
This disorder is associated with dysfunction in brainstem mechanisms that normally inhibit muscle activity during REM sleep. Loss of REM atonia leads to physical enactment of dreams. It is frequently linked to neurodegenerative conditions such as Parkinsonian disorders.

Neurological Associations:
Degeneration of neural pathways regulating REM sleep is a key factor. The disorder may serve as an early marker for neurodegenerative diseases, appearing years before other symptoms.

Risk and Prognostic Factors

Risk Factors:
Older age, male gender, and neurological conditions increase risk. Use of certain medications and substance withdrawal may also contribute.

Prognosis:
The condition is often chronic and may progress, particularly when associated with neurodegenerative disorders.

Treatment

Treatment focuses on preventing injury and reducing symptoms.

Safety Measures:
Ensuring a safe sleep environment by removing sharp objects, padding surroundings, and securing the bed area is essential.

Medical Treatment:
Medications such as clonazepam and melatonin are commonly used to reduce symptoms. Treatment of underlying neurological conditions is also important.

Restless Legs Syndrome

Diagnostic Features

Restless Legs Syndrome involves an urge to move the legs, usually accompanied by uncomfortable sensations. Symptoms worsen during rest and improve with movement, often interfering with sleep.

DSM-5-TR Diagnostic Criteria

A. An urge to move the legs, usually accompanied by uncomfortable sensations.

B. Symptoms begin or worsen during periods of rest or inactivity.

C. Symptoms are partially or totally relieved by movement.

D. Symptoms are worse in the evening or night.

E. The symptoms cause distress or impairment.

F. The symptoms are not attributable to another condition.

Etiology / Causes

Biological Factors:
Biological mechanisms include dysfunction in dopamine pathways that regulate movement and sensory processing. Reduced dopaminergic activity, particularly in the basal ganglia, contributes to the urge to move the limbs. Iron deficiency, especially reduced brain iron levels, is strongly implicated as it affects dopamine synthesis and function. Genetic factors are also significant, particularly in early-onset cases, with familial patterns commonly observed.

Medical and Environmental Factors:
Restless Legs Syndrome is associated with several medical conditions such as chronic kidney disease, diabetes, peripheral neuropathy, and pregnancy. Lifestyle factors, including sleep deprivation, excessive caffeine intake, and sedentary behavior, can worsen symptoms. Certain medications, such as antidepressants and antihistamines, may also exacerbate the condition.

Risk and Prognostic Factors

Risk Factors:
Risk factors include increasing age, female gender, family history, and medical conditions such as anemia and chronic illnesses. Pregnancy, particularly in the third trimester, is a temporary risk factor. Poor sleep hygiene and comorbid mental health conditions like anxiety may further increase severity.

Prognosis:
The disorder is typically chronic with a fluctuating course. Symptoms may worsen over time, particularly in secondary forms associated with medical conditions. However, with appropriate treatment and management of underlying causes, symptoms can be effectively controlled and quality of life improved.

Treatment

Treatment focuses on reducing symptoms and improving sleep quality.

Lifestyle and Behavioral Interventions:
Lifestyle modifications such as maintaining regular sleep schedules, engaging in moderate physical activity, and avoiding caffeine, alcohol, and nicotine can significantly reduce symptoms. Good sleep hygiene practices are essential. Iron supplementation is recommended in individuals with documented deficiency.

Pharmacological Treatment:
Medications that enhance dopaminergic activity, such as dopamine agonists, are commonly used as first-line treatments. Other options include alpha-2-delta calcium channel ligands for sensory symptoms and sleep disturbance. In severe cases, additional medications may be prescribed depending on symptom profile and comorbid conditions.