Introduction:

Nightmares are one of the most frequent sleep disorders in adolescents, which generates a variety of consequences in mental health and school functioning. Prevention is a fundamental strategy at this stage of development, and it is necessary to have reliable instruments for its evaluation.

Objective:

Spanish translation and validation of the NExS in Peruvian adolescents from the general population.

Methodology:

Instrumental and cross-sectional research. A total of 3098 adolescents who responded to the NExS and other psychological variables participated. Statistical analysis was performed using classical test theory and item response theory.

Results:

The NExS presents a unidimensional structure, acceptable reliability, factorial invariance according to sex and relationship with suicidal ideation and depressive symptoms. In addition, item 2 presented the highest discrimination, and the test is more accurate in high levels of nightmares.

Discussion:

In conclusion, the NExS demonstrated adequate sources of evidence of validity for the interpretation of its scores in the measurement of nightmares. Since it is a short instrument, its use in professional practice and research in adolescent population is recommended.