Longitudinal Predictors of Insomnia in a Population-Based Sample of U.S. Military Veterans.

Despite the high prevalence of insomnia among U.S. military veterans, there is limited population-based longitudinal data on its incidence and predictors. Data were analysed from a population-based cohort of 2232 U.S. veterans without insomnia symptoms at baseline who were followed across two assessments over 3 years. The aim was to identify the incidence and baseline predictors associated with incident insomnia, defined as an Insomnia Severity Index score ≥ 15. During the 3-year follow-up period, 128 veterans (weighted 6.0%, 95% confidence interval = 4.8%-7.5%) developed insomnia. Baseline neuroticism emerged as the strongest predictor of insomnia, followed by attention problems, younger age and childhood physical abuse. Together, these factors accounted for 11.1%-29.9% of the explained variance. The predicted probability of incident insomnia increased progressively with the accumulation of these risk factors: 2.4% with none, 7.3% with one, 20.2% with two and 45.0% with three. In conclusion, in this population-based study of U.S. veterans, neuroticism, attentional difficulties, younger age and childhood physical abuse emerged as key predictors of incident insomnia. Results highlight the cumulative impact of these risk factors and underscore the importance of incorporating personality, trauma history and health assessments into clinical care to identify veterans at greatest risk and guide targeted prevention strategies for insomnia.