Sleep problems, except sleep bruxism, sleepwalking, and snoring, can amplify various aspects of dreaming. Among these, sleep paralysis shows the most robust and extensive effects. Sleep onset insomnia and hypersomnia both increase overall dream intensity, but through different pathways: insomnia is linked to stronger dream distortion and paramnesia, while hypersomnia is associated with more vivid perceptual sensations during dreaming. These findings come from a sample of 186 upper secondary school students.
The Nightmare Proneness Scale (NPS) measures a trait-like disposition to frequent nightmares. Among 306 university students, the NPS predicted frequent distressing nightmares independently of psychological distress and negative affect. Three facets emerged: general psychical dysregulation, depressiveness, and somatization. General dysregulation was the strongest predictor of nightmares and the only facet to independently predict them beyond distress and negative affect. The study notes limitations and directions for future research.