A Study On Explicit Suicide Ideation,Implicit Suicide Ideation And Self-Schema:Based On The Interpersonal Theory Of Suicide

BackgroundSuicide has been a worldwide problem in public health,which is a serious threat for humankind.Psychologists have made a great effort to study suicide,finding a series of risk factors,such as mental disease,heredity,stressful life events,inter personal relationship and so on.The suicide ideation is the starting link of the suicide behavior,which gets more and more attention among the researchers.One of the practical methods to prevent the happening of actual suicide is to screen the person who possesses the suicide ideation as early as possible.To date whether a person possesses suicide ideation is,however,dependent on the explicit report by oneself.Because of the high face validity,the effect of this method is partially questioned.Interpersonal Theory of Suicide（IPTS）is a widely concerned theory for the past few years.It interprets the phenomenon of suicide from the angle of interpersonal relationship and contributes some measurements to the suicide prevention.Based on IPTS,Thwarted Belongingness（TB）and Perceived Burdensomeness（PB）have a significant effect on the produce of suicide ideation.At present,most of the studies under the IPTS framework are based on the explicit report and few implicit studies were found by literature review.There is no clear mechanic how TB and PB influence suicide ideation.ObjectiveThe thesis included three parts.Part I was to explore the effectiveness of the Single-category Implicit Association Test（SC-IAT）screening persons who possesses suicide ideation;Part II was to explore the relationship between the TB、PB and the explicit、implicit suicide ideation,confirm preliminarily the cut-off score of the TB and PB in specifying the explicit suicide ideation;Part III was to explore the meditative effect of the self schema between interpersonal needs and the explicit、implicit suicide ideation.All the efforts above were tentative to explore the process of suicidal ideation under the IPTS framework,and to provide theoretical support for screening suicidal sensitive people and formulating corresponding intervention measures.Methods（1）Using standardized procesures,191 young mental patients in general hospital possessing depressive or/and anxious tendency（effective subjects were 162）were measured by the general situation questionnaire,Beck Suicide Inventory（BSI）and SC-IAT compiled by ourselves.Plus,all subjects were questioned whether had a suicide plan in the past 7 days;（2）Using standardized procesures,288 young mental patients in general hospital possessing depressive or/and anxious tendency（effective subjects were262）were measured by the general situation questionnaire,Interpersonal Needs Questionnaire（INQ-15）,BSI,SC-IAT and Self-referent Encoding Task（SRET）compiled by ourselves.Use Excel 2007 to enter the data;Use SPSS 17.0,Medcal and Amos 22.0 to process the data.The statistical methods include descriptive statistics,chi-square test,Spearman correlation analysis,one way ANOVA analysis,two-way ANOVA analysis,analysis of two factors regression,Kruskal Wallis H and construction of structural equation model.Main resultsPart I:（1）The consistency of the two measurement tools was in middle level by the Kappa consistency test（Kappa=0.44,p=0.000）;（2）The D score of suicide plan group was（0.15±0.14）,the D score of suicide ideation group was（0.04±0.09）.Both means are more than 0 with statistical significance by one sample t-test(t(₂₇)=5.57,p=0.00;t(₂₇)=2.07,p=0.048);the D score of control group was（-0.36±0.16）.The mean was less than 0 with statistical significance by one–sample t-test(t(₂₇)=-12.16,p=0.000);（3）There was a statistical significance of difference（p<0.01）among three groups by one way ANOVA(F(_2,81)=111.64,p=0.000).Part II:（1）Bothe rates of explicit and implicit suicide ideation had significant difference under various TB and PB levels by chi-square test（p<0.05）.According to the chi-square segmentation test,the rates of explicit and implicit suicide ideation had significant difference between low TB level、low PB level and high TB level、high PB level;the rates of explicit and implicit suicide ideation had significant difference between median TB level、median PB level and high TB level、high PB level;the rates of explicit and implicit suicide ideation had no significant difference between low TB level、low PB level and median TB level、median PB level.（2）Explicit suicide ideation as the dependent variable,the main effect of TB was significant by two way ANOVA(F(_1,87)=11.21,p=0.001);the main effect of PB was significant by two way ANOVA(F(_1,87)=58.07,p=0.000);the cross effect of TB and PB was significant(F(_1,87)=11.02,p=0.001);（3）Implicit suicide ideation as the dependent variable,the main effect of TB was significant by two way ANOVA(F(_1,87)=6.02,p=0.016);the main effect of PB was significant by two way ANOVA(F(_1,87)=21.63,p=0.000);the cross effect of TB and PB was not significant(F(_1,87)=0.05,p=0.832);（4）The ranking of risk factors relevant to the explicit suicide ideation were PB（OR=4.44,95%CI=2.48⁷.93,p=0.000）、depression（OR=3.36,95%CI=2.16⁵.22,p=0.000）and TB（OR=1.66,95%CI=1.01².75,p=0.047）;the ranking of risk factors relevant to the implicit suicide ideation were PB（OR=2.67,95%CI=1.59⁴.47,p=0.000）、depression（OR=2.14,95%CI=1.41³.23,p=0.000）and TB（OR=1.80,95%CI=1.15².83,p=0.011）.（5）According to the ROC,explicit suicide ideation as the gold standard,the AUC of TB was 0.71（95%CI=0.66⁰.77）,the cut-off score was 2.89,Youden Index was 0.40;the AUC of TB was 0.82（95%CI=0.76⁰.86）,the cut-off score was 2.00,Youden Index was 0.54;Part III:（1）According to the Kruskal Wallis H,various kinds of self schema had significant effects on explicit and implicit suicide ideation（Hc=48.14,p=0.000;Hc=144.66,p=0.000）;（2）The relationship among all variables were significant by Spearman relevance analysis（p<0.01）,the TB、PB and the explicit、implicit suicide ideation was in positive correlation（r=0.25⁰.48）;the self schema and the explicit、implicit suicide ideation was in negative correlation（r=-0.42、-0.64）.（3）According to the bias-corrected percentile Bootstrap,after 5000 times random sampling,the 95%confidence interval of mediating effect of self schema in explicit suicide ideation model was（-0.09,0.19）（including 0）,indicating that the mediating effect of self schema was not significant in explicit study;the 95%confidence interval of mediating effect of self schema in implicit suicide ideation model was（0.07,0.14）（not including 0）,indicating that the mediating effect of self schema was significant in implicit study;（4）Structural equation modeling indicates that the fit indices wereχ2/df=9.62,p=0.002,GFI=0.98,AGFI=0.82,RMSEA=0.07,NFI=0.90,CFI=0.90 in explicit suicide ideation modeling;the fit indices wereχ2/df=6.14,p=0.013,GFI=0.99,AGFI=0.88,RMSEA=0.04,NFI=0.95,CFI=0.96 in implicit suicide ideation modeling.Both models fit well.Conclusions（1）SC-IAT was able to evaluate the suicide ideation,which was an important supplement to the explicit instrument;（2）Both TB and PB had significant effects on explicit and implicit suicide ideation.Plus,they were the risk factors of explicit and implicit suicide ideation;（3）The subscales of TB and PB in INQ-15 were sensitive to explicit and implicit suicide ideation respectively,the cut-off score respond to explicit suicide ideation was got preliminarily;（4）Self schema had significant effects on both explicit and implicit suicide ideation;（5）The mediating effect of self schema between interpersonal needs and explicit suicide ideation was not significant;the mediating effect of self schema between interpersonal needs and implicit suicide ideation was significant.