Sleep problems in children and adolescents following traumatic life events

Table 1 Hypothetical mechanisms by which traumatic exposure may affect sleep

Hypothesis	Mechanism
Biological perspective	Physiological arousal (increased activity of the amygdala, and decreased activity of the medial prefrontal cortex) hinders sleep onset
Safety and attachment	Feeling that one needs to be continuously alert and on guard instead of sleeping
Emotional memory and affect	Alterations in nightmare rates, severity, and comorbidity reflect the influence of both affect load and distress
Threat simulation theory	Threat simulation in the course of dreaming reenacts the cognitive mechanisms needed for adequate threat perception and threat avoidance
Emotional regulation model	Individuals exposed to trauma continue to be hyper-alert to defend themselves against real or imagined hazards, such as through distressing dreaming that replays the traumatic experience during sleep
Hyperarousal-based theory	Under a hyper-arousal state, trauma survivors show an increased level of awareness and a sensitized response to the external world
Anxiety buffer disruption assumption	Fear can increase the likelihood of gathering traumatic cues in the cognitive world, resulting in intrusive thoughts
Depressive-like pathophysiology	Elevated plasma cortisol levels near sleep onset, increased sleep latency, and significant dysregulation in REM sleep patterns
Cognitive hyperactivation	Excessive worry, rumination, and negative attributions contribute to the hyperarousal interfering with sleep

REM: Rapid eyes movement.