The role of vulnerability in stress-related insomnia, social support and coping styles on incidence and persistence of insomnia.

Individuals who are more prone to experience situational insomnia under stressful conditions may also be at greater risk to develop subsequent insomnia. While cross-sectional data exist on the link between sleep reactivity (heightened vulnerability to stress-related insomnia) and insomnia, limited data exist on its predictive value. The aim of the study was to evaluate prospectively whether sleep reactivity was associated with increased risk of incident and persistent insomnia in a population-based sample of good sleepers. Social support and coping styles were also investigated as potential moderators. Participants were 1449 adults (Mage  = 47.4 years, standard deviation = 15.1; 41.2% male) without insomnia at baseline and evaluated four times over 3 years. Sleep reactivity was measured using the Ford Insomnia Response to Stress Test (FIRST). Additional measures included depressive symptoms, the frequency and perceived impact of stressful life events, social support and coping styles. After controlling for prior sleep history, depressive symptoms, arousal predisposition, stressful life events and perceived impact, individuals with higher sleep reactivity had an odds ratio (OR) of 1.56 [95% confidence interval (CI): 1.13-2.16], 1.41 (95% CI: 0.87-2.30) and 2.02 (95% CI: 1.30-3.15) of developing insomnia symptoms, syndrome and persistent insomnia, respectively. Social support and coping styles did not moderate these associations. Results suggest that heightened vulnerability to insomnia is associated with an increased risk of developing new-onset subsyndromal and persistent insomnia in good sleepers. Knowledge of premorbid differences is important to identify at-risk individuals, as this may help to develop more targeted prevention and intervention strategies for insomnia.