The Relationship Between The Related Factors And The Serum Level Of Brain-derived Neurotrophic Factor In Suicidal Mental Disorder Patients

Objective To investigate the related factors contributing to the serum level of brain-derived neurotrophic factor(BDNF) in suicidal mental disorder patients and to explore the possible role of BDNF in.suicidal behavior of mental disorder.Methods All subjects had not taken antidepressants and benzodiazepine and psychotric medications whthin the last two weeks on admission.(1)The first study examined serum BDNF levels in 23 major depressive disorder(MDD) patients who had recently attempted suicide,24 non-suicidal MDD patients and 30 sex- age- and education matched healthy normal controls.The Hamilton Depression Rating Scale-24 items(HAMD₂₄),the Beck Helpless Rating Scale(BHS) and the Self-rating Idea of Suicide Scale(SIOSS) was used to evaluate the severity of symptoms.The serum level of BDNF was detected with sandwich ELISA.Person correlation coefficients was used to measure the correlations between serum BDNF and related illness variables.(2) The second study examined serum BDNF levels in 20 schizophrenia patients who had recently attempted suicide,28 non-suicidal schizophrenia patients and 30 sex- age- and education matched healthy normal controls.The Brief Psychiatric Rating Scale(BPRS) and the Self-rating Idea of Suicide Scale(SIOSS) was used to evaluate the severity of symptoms.The serum level of BDNF was detected with sandwich ELISA.Person correlation coefficients was used to measure the correlations between serum BDNF and related illness variables.Results(1) There were significant differences in the serum level of BDNF between the suicidal MDD patients,non-suicidal MDD patients and normal controls(F=21.927, P＜0.05).Post hoc analysis showed the serum BDNF levels in the suicidal MDD patients were lower than that in non-suicidal MDD patients(P＜0.05),the serum BDNF levels were lower than that in normal controls.In suicidal MDD patients,the serum BDNF of the suicidal MDD patients was negatively correlated with severity of suicide and helpless. (2) There were significant differences in the serum level of BDNF between the suicidal schizophrenia patients,non-suicidal schizophrenia patients and normal controls (F=32.395,P＜0.01).Post hoc analysis showed the serum BDNF levels in the suicidal schizophrenia patients were lower than that in non-suicidal schizophrenia patients (P＜0.05) and the serum BDNF levels were lower than that in normal controls.In suicidal schizophrenia patients(P＜0.01);The serum BDNF of the schizophrenia patients,who had recently attempted suicide was negatively correlated with severity of suicide.Conclusions(1) our results suggest that reduction of serum brain-derived neurotrophic is related to suicidal behavior in major depression.(2) Our results suggest that reduction of serum brain-derived neurotrophic may increase suicidal risk of Schizophrenia patients.