In the etiopathogenesis of primary insomnia, three
points should be considered: predisposing (genetic and
constitutional), precipitating and perpetuating factors.
Predisposing factors depend on hyperactivity of the
awakening system (stress response mechanisms), hyperactivity
of the hypothalamic-pituitary-adrenal axis,
anxiety and depression, abnormalities in the mechanisms
of sleep-wakefulness homeostasis, abnormalities
in the circadian rhythm (circadian sleep-wakefulness
control) and abnormalities of the intrinsic mechanisms
of sleep-wakefulness contro