The Relation Between The Dream Threat Level, Life Events And Childhood Trauma In Depressive Patients

Objective Revonsuo put forward the dream threat simulation theory.This theory state that dream consciousness is essentially an ancientbiological defence mechanism, evolutionarily selected for its capacity torepeatedly simulate threatening events. Threat simulation during dreamingrehearses the cognitive mechanism required for efficient threat perceptionand threat avoidance, leading to increased probability of reproductivesuccess during human evolution. Some of the theory`s assumptions wereconfirmed in the general population studies. The dream threat simulation, asan adaptive reaction, may be affected by multiple factors wich includechildhood trauma and current stress level. This study assume that thechildhood trauma experience will influence the dream threat simulationlevel, and may mediate the effects of the event of stress. This study is tosurvey the threat simulation level in depressive patients, and to explore therelationship among dream threat level, life events and childhood trauma indepressive patients. The Dream Threat Questionnaire (DTQ) was developedand its reliability and validity were tested.Methods In study one,55patients with major depression and51healthy controls were tested with Dream Threat Questionnaire（DTQ),Childhood Trauma Questionnaire (CTQ) and Life Events Scale (LES). Thedream threat level were compared between the tow groups, and correlationand regression analysis were used to research the relationships of thevariables for patient`s data. In study two, The DTQ were developed on thebases of data from the threat simulation theory and interview with20normal and20neurotic and depressive patients, The reliability and validity of thequestionnaire were anylyzed in484normal people,166people experiencedWen Chuan earthquake and121patients with mental disorders.Results In study one, compared with the healthy controls, patients hadsignificantly higher DTQ score (1.49±2.32vs2.91±2.98, P<0.01).Correlation analysis showed that dream threat level, negative life events andchildhood trauma were significantly positively correlated each other.Regression analysis indicated childhood trauma directly predicted dreamthreat level（β=0.041,P<0.05）and completely mediated the relationshipbetween negative life events and dream threat level. In study two, TheCronbach α coefficient was0.799, the split coefficient was0.775, and thetest retest reliability was0.872. Factor analysis results indicated thequestionnaire has one factor which explain37.5%of variance, and factorloading for all items of DTQ ranged from0.41~0.75. Confirmatory factoranalysis suggested a good fit between the sample data and hypothesizedmodel. The score of DTQ showed a significant correlation with the score ofnightmare frequency (r=0.54, P<0.001) and the score of threat dreamfrequency (r=0.69,P<0.001) in dream diary. Compared with the non-traumagroup(1.3±1.9), the trauma group (2.2±2.4) had higher DTQ score（z=2.929,P=0.003）.Conclusion Study one show that depressive patients have high threatsimulation level in their dreams, and childhood trauma experience is asignificant factor influencing dream threat level, as a complete mediator bywhich life events influence dream threat level. Study two indicate that DTQhas good psychometrics properties, with adequate reliability and validity,and can be applicable to assess the threat level of dream in Chinesepopulation.