Study objectives: To determine the prevalence of frequent nightmares and their correlates in a large community-based cohort of middle-aged Hong Kong Chinese.
Design: A 2-phase design involving a cross-sectional survey of 8558 subjects (men, 47.6%) with a mean age of 40.9 years (SD 5.5, range 20-78) and subsequently followed by a detailed clinical evaluation of the psychopathology and personality profile of 252 subjects.
Measurements and results: The prevalence of frequent nightmares, as defined by at least once per week, was 5.1%. Female sex, low monthly family income, insomnia symptoms, sleep-disordered breathing symptoms, and sleep-related daytime consequences were significantly associated with nightmare frequency. The risk of having a psychiatric disorder was 5.74 times greater for subjects with frequent nightmares (95% confidence interval 2.03-16.26), especially mood disorders (odds ratio = 15.57, 95% confidence interval 3.77-64.37). After exclusion of concomitant psychiatric morbidities, subjects with frequent nightmares still scored significantly higher on neuroticism in the personality scale (p < 0.05).
Conclusions: Frequent nightmares were not uncommon in the general population and were associated with a constellation of factors, including sociodemographic characteristics and comorbid sleep and psychiatric disorders. Moreover, frequent nightmares were independently related to the neuroticism personality trait, irrespective of psychiatric diagnosis. Prospective studies should be conducted to investigate various predisposing, precipitating, and perpetuating factors and the associated repercussions of nightmares.