The Nightmare Disorder Index Chinese Version (NDI-CV) shows good psychometric properties for measuring nightmare impact in Chinese adolescents. Among 6,014 adolescents who completed the NDI-CV along with measures of nightmare distress, sleep quality, insomnia, daytime sleepiness, anxiety, and depression, the questionnaire demonstrated strong internal consistency with a Cronbach's α coefficient of 0.876. Test-retest reliability was assessed in 423 adolescents after a 2-week interval, with a correlation coefficient confidence interval of 0.675-0.977. The findings indicate the NDI-CV is a valid and reliable instrument for assessing nightmare disorder in this population.
Nightmares, insomnia, depression, and anxiety are all linked to cognitive deficits in adolescents. An online survey of 6,014 adolescents found that females, senior high school students, and those with poor academic performance reported more nightmares, insomnia, and cognitive deficits; city dwellers had higher depression and anxiety scores. Cognitive deficits were positively correlated with nightmares, insomnia, depression, and anxiety. Insomnia, depression, and anxiety together acted as a chain mediating the relationship between nightmares and cognitive deficits: nightmares appear to affect cognition indirectly by first worsening insomnia, which then worsens depression and anxiety. Because the study was cross-sectional, causal relationships could not be determined, and reporting or volunteer bias may exist. Early identification and treatment of frequent nightmares may help reduce negative outcomes.