The comparison of children who diagnosed with major depressive disorder, their healthy siblings and healthy controls with childhood trauma, thyroid function and dexamethasone suppression tests

Background: The aim of the study is to evaluate patients with MDD, their healthy siblings and control group with childhood trauma, fT3, fT4, TSH and dexamethasone suppression test. The biological effects of childhood trauma and depression were investigated. Unlike the siblings of the patients, we started to investigate the causes of psychopathology. Material and Methods: The study was conducted between December 2016 and 2017. Three groups were included the study: Group 1 contains the patients had major depressive disorder diagnosis according to DSM-V diagnostic criteria who applied to Department of Psychiatry of Düzce University Faculty of Medicine and will be able to understand and answer the given scale appropriately (Group 1), healthy, close age and grew up in the same environment siblings of patients we selected for the first group (Group 2) and healthy control group (Group 3). Socio-demographic form, Beck Depression Inventory (BDI), Childhood Trauma Scale (CTQ-28), and Eysenck Personality Inventory (EPI) were applied to all participants. They also were tested for 1 mg dexamethasone suppression and baseline thyroid hormones were assessed. Results: The BDI score of the patient group was significantly higher than that of sibling and control (p<0,001). BDI scores were also associated with all CTQ subtypes in the MDD patient group. The fT4 values in the patient and sibling groups were significantly lower than the control group (p<0,001). In addition, the sibling group's cortisol level was significantly lower than the control group (p=0,028). Patient and sibling group reporting physical neglect were significantly lower fT4 value than the control group (p<0,001; p=0,033). The fT3/fT4 ratio of the patient and sibling group reporting physical abuse was significantly higher than the control group (p=0,034). Significant low fT4 and low cortisol levels were obtained in participants who attempted suicide. Conclusion: In our study, we found that childhood trauma affects biological markers, fT4 and cortisol levels are lower in childhood trauma supported by the literature, but depression has less effect. Long-term trauma caused HPA and HPT axis changes. We also found low fT4 and low cortisol associated with suicide attempts. Our findings suggest that long-term traumas are more likely to cause neuroendocrine changes than depression. We found similar biological changes in the patient and sibling group who were traumatized together.