Prospective study of predictors and consequences of insomnia: personality, lifestyle, mental health, and work-related stressors.

Objective: To prospectively investigate the reciprocal relationships between personality traits, lifestyle factors, mental health, sleepiness, and work-related stressors against insomnia.

Methods: A total of 799 Norwegian shift-working nurses (mean age 33.2 years, 90% female) participated in this prospective cohort study.