Cognitive Processing Disorder Associated With Depression After Burns

Depression is one of the most frequent emotional disorder. Epidemiologic studies found that the morbidity rised up year by year, especially after major life events occurred. Depression is associated with low spirit, lack of interests, hysteresis of psychomotor and hopeless which leads to suicide or susceptibility of other desease. Burn patients are extremely likely to develop mental disorders, particularly depression, due to long periods of therapy, sleep disorder, pain, disfigurement of face, functional disability, interpersonal disorders, and social adaptation deficiency, Although the cure rate of severe burn patients has been increasing, the pattern of psychological therapy and counseling for burn patients is still under investigation.Studies on depression after burns are mainly focused on the epidemic status, developmental characteristics and influential factors. However, the interaction of influential factors is seldom studied.Cognition is a composite function of attention, thought, analyses, study, memory and information transfer. When multiple and complicated information stimulate the cognitive system, they can not be accepted in the same time. Therefore, the selection of information, transference of attention and remember of cognitive process are very important. Theories about cognitive disorder associated with depression propose that automatic thoughts and preferential processing of negative material play an important role in the onset, maintenance, and recurrence of depressive episodes. There is no report on cognitive processing disorder associated with depression after burns.Hippocampus is one of the most important encephalic regions for cognition and memory. Hippocampus contains many glucocorticoid receptors which are susceptive to cortisol. In normal condition, hippocampus participates in the feedback regulation of hypothalamic-pituitary-adrenal by inhibiting the release of corticotrophin -releasing factor and then decreasing the adrenocorticotropic hormone and cortisol release when the density of cortisol is too high, While under chronic or long-term stress, the disorder of feedback regulation leads to hippocampus neurone atrophy which aggravates the cognitive disorder.We presume that hippocampus and HPA play a role physiologically in cognitive processing disorder associated with depression after burns. There is still no such report.This study contains three parts. First, through studying the morbidity status, character and influential factors to analyze the potential physiological, psychological, social dangerous factors. Second, through studying the attention spatial distribution, attention shift and recognition to emotional pictures, we analyze the cognitive biases of depression after burns.And through glucide fluid intake, open-field, water maze,suttle box experiments to observe the cognitive and behavior changes of depression rats after burn model. At last, through studying the exchange of CRF, ACTH and Cortisol in blood , the hippocampus structure damage,express of CRFmRNA in hypothalamus of the depression after burn rats to analyze the neuromechanism of depression after burns.The results of this study are as follows:1. The morbidity of depression after burns is 65.4%, among which 9.6% is serious, 26.7% is midrange, 29.1% is light. The morbidity of female is higher than male, and that in rehabilitation period is higher than in therapeutic period, and that in the patients with special area burns such as hands and face is higher than in the patients without special area burn, et al.2. No matter from the reaction time and the accurate rates, the patients of depression after burns has cognitive bias in the spatial distribution of attention.They have over alert tendency to the negative pictures,even in the early cognitive stage. This bias has also been found in the burn patients without depression.3. Negative cognitive processing bias is also found in the attention shift stage.It shows that depression patients after burns are not easily to shift their attention from the negative pictures and the accurate rate to the target is lower. There is no such bias in the burn patients without depression and the control groups.4. The negative cognitive processing bias of recognition stage is found in burn patients with depression.They neglect more positive pictures intentionally and recognize more negative pictures correctly. There is no such bias in the burn patients without depression and the control groups.5. The behaviour of the depression after burn rats significantly changed, such as lack of interesting, slow in the action, spatial study and memory ability decrease.6. The espress of CRFmRNA in hypothalamus of the depression after burns are significantly higher than the other groups.7. The level of CRF, ACTH and Cortisol in the depression after burn rats'blood are higher than the rats without depression.8. The structure and function of neurons and glia in the hippocampus of depression after burn rats changes, especially in CA3 and dentate gyrus.While the express of NMDA decrease in dentate gyrus significantly.Conclution:1. The morbidity of depression after burns is very high. There exist significant differences in sexuality, stage of disease and special parts of burn.It is also influenced significantly by the automatic thoughts, coping style, communication ability,psycho status before burn,social support,et al.2. The patients of depression after burns have significantly cognitive bias to negative pictures.This negative bias of cognitive may be the important factor of depression after burns.3. We establish depression after burn model with 30%TBSA second degree burn combine chronic mild stress successfully.The depression after burn rats show similar cognitive and behaviour change of the depression after burn patients.4.Hippocampus plays very important role in depression after burns. It can interfere the cognition and behavior ability directly through neuron and glia plastic and also can change that through regulating HPA.