Do night terrors indicate that the central nervous system (CNS) is activated due to stress?

Night Terrors and Central Nervous System Activation from Stress

Night terrors are associated with central nervous system hyperarousal, which can be triggered or exacerbated by stress, particularly in PTSD-associated cases where elevated CNS noradrenergic activity plays a key role in their pathophysiology. 1, 2

Relationship Between Night Terrors and CNS Activation

Neurobiological Mechanisms

• Night terrors typically occur during arousal from stage three or four non-rapid eye movement (NREM) sleep, within the first three hours of sleep 3
• In PTSD-associated nightmares (which share mechanisms with night terrors), norepinephrine plays a critical role in pathophysiology 1:
  • Elevated norepinephrine levels in cerebrospinal fluid and urine
  • CSF norepinephrine concentration correlates with severity of PTSD symptoms
  • Consistently elevated CNS noradrenergic activity disrupts normal sleep architecture

Clinical Evidence of CNS Activation

• Autonomic hyperactivity during night terrors manifests as 3:
  • Tachycardia and tachypnea
  • Diaphoresis and flushed face
  • Dilated pupils
  • Agitation and tremulousness
  • Increased muscle tone

Stress as a Trigger

• The American Academy of Sleep Medicine identifies stress and anxiety as significant factors associated with nightmare disorders 1
• PTSD-associated nightmares are part of the intrusive/re-experiencing symptom cluster, but also connect to the hyperarousal symptom cluster 1
• Up to 80% of PTSD patients report nightmares, indicating a strong connection between stress-related conditions and sleep disturbances 2

Differential Features: Night Terrors vs. Nightmares

Night Terrors

• Occur during NREM sleep (stages 3-4)
• Patient is difficult to arouse and console
• Retrograde amnesia for the event
• Autonomic hyperactivity is prominent
• Peak incidence between 5-7 years of age 3

Nightmares

• Occur primarily during REM sleep
• Full alertness upon awakening
• Clear recall of dream content
• Less pronounced autonomic features
• Can occur at any age but common in children 1

Treatment Implications

Pharmacological Approaches

• Prazosin (an α1-adrenergic antagonist) is recommended for PTSD-associated nightmares (Level A evidence) 1

  • Works by reducing CNS adrenergic activity
  • Starting dose 1mg at bedtime, increased by 1-2mg every few days
  • Average effective dose approximately 3mg (range 1-10mg)

• Clonidine (an α2-adrenergic receptor agonist) may be considered (Level C evidence) 1

  • Suppresses sympathetic nervous system outflow throughout the brain
  • Shares therapeutic rationale with prazosin

Non-Pharmacological Approaches

• Image rehearsal therapy (a modified cognitive behavioral technique) shows efficacy 1
• Good sleep hygiene and appropriate sleeping environment are essential 3
• Anticipatory awakening approximately 30 minutes before typical episode time can be effective for frequent night terrors 3

Important Clinical Considerations

• Night terrors in children are usually benign and self-limiting, with 50% resolving by age 8 years 4
• Persistent night terrors into adulthood may indicate underlying psychopathology or stress disorders 5, 6
• Sleep deprivation can predispose to night terrors, emphasizing the importance of adequate sleep 3
• Attempts to interrupt a night terror episode should be avoided as this may increase agitation 3

The evidence strongly supports that night terrors, particularly those associated with PTSD or chronic stress, involve CNS hyperarousal with elevated noradrenergic activity. The effectiveness of medications that reduce CNS adrenergic activity in treating these conditions further confirms this relationship.