Abstract: Objective To analyze the risk factors of attempted suicide in young male soldiers with mental disorders,and provide reference for early prevention and control of suicide in military personnel. Methods From June 2021 to March 2022,60 young male military personnel diagnosed with mental disorders were enrolled consecutively,divided into attempted suicide group（33 cases） and non attempted suicide group（27 cases）.Sociodemographic and clinical characteristics data of the two groups were collected,and Beck depression inventory（BDI）,insomnia severity index（ISI）,and military social support rate scale for Chinese military personnel（SSRS-M） were used to evaluate serum serotonin（5-hydroxytryptamine）.The concentrations of droxytryptamine（5-HT） and brain-derived neurotrophic factor（BDNF） were measured to compare the differences between the two groups.Multiple logistic regression analysis was used to understand the risk factors for attempted suicide in this population. Results Compared with the non attempted suicide group,the attempted suicide group had a higher proportion of previous multiple hospitalizations（57.58%vs 29.63%,P<0.05）,more traumatic experiences（66.67% vs 40.74%,P<0.05）,stronger suicidal ideation（72.73% vs 37.04%,P<0.01）,and more common suicidal plans（90.91% vs 59.26%,P<0.01） and non suicidal self injury（NSSI） behaviors（93.94% vs 48.15%,P<0.01）,with statistically significant differences（all P<0.05）. The total score of SSRS-M in the attempted suicide group was significantly lower than that in the non attempted suicide group[（24.85±6.48）points vs（28.70±7.15）points,P<0.05].The serum BDNF concentration in the attempted suicide group was lower[418.26（269.18,606.62）ng/L vs 537.46（412.04,784.92）ng/L,P<0.05]. Logistic regression analysis showed that the presence of NSSI behavior（OR=13.06） and low serum BDNF concentration（OR=0.97） were the main risk factors for attempted suicide in military patients with mental disorders（both P<0.05）. Conclusions NSSI behavior and low serum BDNF levels may be independent risk factors for attempted suicide in military patients with mental disorders,and can be used as early warning signals for suicide prevention and control,which is of great significance for military suicide prevention and control.

Key words: Mental disorders, Suicide Attempt, Non-suicidal self-injury, Brain-derived neurotrophic factor