Trait-State Interactions in the Etiology of Nightmares

Various personality and psychopathology traits are associated with nightmare frequency. This study investigated whether trait variables might also account for individual differences in the longitudinal relationship between daily mood and nightmare incidence each night. Forty-two participants (35 women, 7 men; mean age = 40.10 years) reported having nightmares at least once per month and completed a 14-day dream and mood (anxiety and depression) log. Within-subject correlations between state anxiety and nightmare incidence or absence the following night and between state depression and nightmare incidence or absence were computed. None of the trait measures had significant correlations with these within-subject correlations. However, when only participants scoring above the group median on Hartman's thin boundariness were analyzed, thin boundariness, Symptom Checklist-Global Severity, adverse life events, and childhood adversity were associated with the incidence of nightmares as a function of state anxiety or depression on a night-by-night basis, with correlation coefficients between .43 and .52. This supports the hypothesis of trait predispositions for a nightmare reaction to daily state anxiety or depression.