Study objectives: The relationship between nightmare prevalence, nightmare distress, and self-reported psychological disturbance was assessed prospectively.
Design: Differences in self-reported psychological disturbance as a function of nightmare prevalence was investigated by MANCOVA's with non-nightmare dreams as the covariate as well as Pearson correlations. The relative contribution of nightmare prevalence and distress to the prediction of psychological disturbance was investigated through multiple regression analyses.
Participants: 116 participants (mean age = 20 years) completed self-report indices of depression, anxiety, dissociation, psychosis-proneness, and a psychiatric symptom checklist and kept a nightmare log for 21 consecutive nights.
Measurements and results: Frequent nightmares were associated with higher levels of psychological disturbance. Individuals who reported 3 or more nightmares across the 3 weeks reported more dissociation, psychosis-proneness and psychiatric symptoms than participants reporting 2 nightmares or less. However, nightmare prevalence and distress were not significantly correlated and differentially predicted to different types of waking psychological disturbance. Multiple regressions further indicated that nightmare distress accounted for much of the unique explanatory variance in predicting clinical states associated with high negative affect (anxiety and depression). Last, there was no evidence for a specific relationship between nightmares and psychosis-proneness.
Conclusions: The findings suggest that it is not the incidence of nightmares which is associated with poorer waking psychological functioning, especially anxiety and depression states, but the reported distress associated with the nightmare experience which is the critical variable in predicting higher psychological disturbance.