Validity, Reliability, and Incremental Prediction of Nightmares Using a Shortened Form of the Nightmare Proneness Scale (NPS-6)
Author(s): William E. Kelly
Abstract: Previous research proposed a shortened 6-item version of the Nightmare Proneness Scale (NPS-6) to assess nightmare proneness, a trait-like disposition toward frequent nightmares. Comprehensive psychometric evaluation, however, remained limited. Three studies (N = 543 adults) examined the factorial structure, validity, and temporal stability of the NPS-6. Results supported a unidimensional structure and adequate internal consistency. The NPS-6 demonstrated substantial yet partially distinct associations with hypothesized core processes (emotional dysregulation, vulnerability, concretization) as well as neuroticism and nightmare frequency. Discriminant validity was evidenced by negligible correlations with social desirability and sleep length. The NPS-6 predicted nightmares beyond sociodemographic and related affective variables, supporting incremental validity. One-month retest reliability was .902. Findings suggest the NPS-6 provides a reliable, temporally stable, and distinct measure of nightmare proneness suitable for efficient assessment in individual differences research.
Keywords: Nightmare proneness; Nightmares; Emotional dysregulation; Vulnerability; Concretization; Neuroticism
Published: February 27, 2026
Article: e24003
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