The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) will be used to determine depression, Hamilton Depression Rating Scale (HAMD) will be used to evaluate the severity of depression, and plasma biomarkers (including interleukin 1, interleukin 6 and interleukin 10) will be tested to determine the underlying mechanisms. The gene discussed is IL6; the disease is depressive symptom measurement.