Psychological Strain In Relation To Suicide Attempt Aged 15-50 In Rural China

1 BackgroundBoth suicide and suicide attempt are a major public health issue worldwide.Suicide attempters are more prone to experience repeated suicidal behavior.Studies have shown that about 25%of suicide attempters have repeated suicidal behavior,10%of which eventually lead to death.Risk factors of suicide are complex,including sociology,psychology and psychiatry,but these factors are the superficial reasons which can only explain social and psychological conditions before his or her suicide.So we must explore the root causes of suicide.Based on a lot of western suicide theories,and taking social conditions and psychological characteristics into consideration,Zhang Jie developed the Strain Theory of Suicide to explain the root causes of suicide.Strain was inconsistent pressure,which came from two or more competing ideas of individuals.There were four different sources of psychological strain:conflict between different values,deviation of aspirations and reality,relative deprivation,and lack of coping skills for a crisis.External stimulus might cause inconsistent pressure,which might lead to social psychological problems or mental disorders,and finally lead to suicide.The development of Strain Theory has undergone a series of progress,and the measurement of Strain has also been transformed from the original multiple subscales into the Psychological Strain Scale(PSS).The reliability and validity of Chinese and English version of PSS has been verified in college student population,but the measurement and function of Strain has not been verified in suicide researches.2 Objectives(1)To explore characteristics of strain among rural residents aged 15-50,and to evaluate the reliability and validity of Psychological Strain Scale;(2)To evaluate the effect of strain on suicide attempt by gender and age group,and to explore the relationship between different types of strain and suicide attempt in rural China;(3)To construct the Suicide Attempt Strain Model,and to explore the relationship between psychological strain and suicide attempt in multiple perspectives;(4)To explore the occurrence of repeated suicidal behaviors and the outcome ofpsychological status between high and low strain group;and to provide advice for suicide prevention.3 Methods3.1 SubjectsThe suicide attempters came from the Disease Surveillance Points of Shandong Province,and were obtained in two stages.In the first stage,we selected the cases during October 1,2009 to March 31,2011 from six rural counties(Zoucheng,Jyunan,Tengzhou,Penglai,Lijin and Ningyang).In the second stage,we selected the cases during January 1,2014 to June 30,2015 from the five rural counties(Zoucheng,Jyunan,Xintai,Zhangqiu and Yishui).The controls in the same areas with the same age(no more than 3 years)and gender matched to the suicide attempters were selected by local village doctors.The controls were also required to have no blood relationship with the suicide attempters and have no suicide history.3.2 MeasurementFace-to-face interviews were used to collect the information of subjects.All process included two stages:the first interview and the follow-up survey.The follow-up survey interviewed all the subjects from the first survey,including suicide attempters and normal controls.We interviewed subjects themselves and informants instead if subjects themselves were loss to follow up.Upon the interviewee’s written informed consent,the interview was conducted by the trained interviewer.The questionnaires included four parts:basic information questionnaire,suicidal behavior questionnaire,standard scales(Psychological Strain Scale,Life Event Scale,Self-esteem Scale,Center for Epidemiologic Studies Depression Scale,State-Trait Anxiety Inventory,and Duke Social Support Index),and Structured Clinical Interview,forDSM-IV.3.3 Statistical analysisSPSS 24.0,Amos 17.0 and GMDR 0.9 were used to analyze data.Chi-Square test and t test were used for descriptive analysis.Conditional logistic regression model was performed to explore association between measured variables and suicide attempt.Generalized Multifactor Dimensionality Reduction(GMDR)was used to explore higher-order interaction effect of Strain and suicidal related risk factors.Structural equation model of strain,mental factors,social psychological factors and suicide attempt was constructed to explore potential explanation of association between strain and suicide attempt.All significant levels were set at P<0.05.4 Results4.1 Sample characteristicsBy design,412 suicide attempters and 412 normal controls were matched in the first survey,in which the male attempted suicides were 126(30.6%),the female were 286 cases(69.4%),and the male/female ratio was 1:2.3.The average age of suicide attempters was 37.33±9.05 years old.In the follow-up survey,we interviewed 352 suicide attempters and 348 normal controls,and the follow-up rate was 84.95%.4.2 Reliability and validity of Psychological Strain ScaleThe reliability of Psychological Strain Scale was high.Cronbach’s a of Psychological Strain Scale in the total population was 0.947.Cronbach’s a of the scale in the suicide attempters and normal controls were 0.947 and 0.940,respectively.In the confirmatory factor analyses,Goodness of Fit Index(GFI)and Comparative Fit Index(CFI)were more than 0.7,and Adjusted Goodness of Fit Index(AGFI)was more than 0.65 in both suicide attempts and control groups.Root Mean Square Error of Approximation(RMSEA)were 0.090 and 0.091 in suicide attempts and controls,respectively.4.3 Distribution of psychological strainsIn the two stage surveys,suicide attempters scored significantly higher than controls on four types of strain.Both coping strain and aspiration strain were the top two scores in the cases and controls.Compared with the first survey,all the four types of strain significantly decreased in the follow-up survey,and as the follow-up intervals lengthened,the level of reduced susceptibility is abating.Stratified by gender,female scored significantly higher than male on copingstrain both in the suicide attempts(P=0.016)and the controls(P<0.001).The scores for aspiration strain(P<0.001)and relative deprivation strain(P=0.005)between male and female were also significantly different in controls,but not in suicide attempts.Stratified by age,old-age group scored significantly higher than young-age group on relative deprivation strain both in the suicide attempts(P=0.036)and the controls(P=0.006).Beside,old-age group also scored significantly higher than young-age group on coping strain in the controls(P=0.021).4.4 Association between strain and suicide attemptMultivariate conditional Logistic regression analyses showed that,in the total population,value strain(OR=1.09,95%CI:1.04～1.15),aspiration strain(OR=1.06,95%CI:1,02～1.10),relative deprivation strain(OR=1.06,95%CI:1.02～1.10),and coping strain(OR=1.09,95%C:1.05～1.14)were positively associated with suicide attempt.Stratified by gender,value strain was significantly associated with female suicide attempts(OR=l.11,95%CI:1.04-1.18).Both aspiration strain(OR=1.10,95%CI:1.01～1.19)and relative deprivation strain(OR=1.19,95%CI:1.06～1.32)were significantly associated with male suicide attempts.Besides,high coping strain was a common risk factor of suicide attempt for both male and female(OR=1.17,95%CI:1.05～1.30;OR=1.08,95%CI:1.02～1.13).Generalized Multifactor Dimensionality Reduction method(GMDR)showed that the higher-order interaction effect of education level,negative life events,psychiatric disorder,and Strain exist in suicide attempts.In the structure equation model analyses,(1)psychological strains influencedsuicide attempt directly,and the standardized path coefficient was 0.41;(2)social factors were strongly associated with strain,and the correlation coefficient was 0.70.The standardized path coefficients for social factors and suicide attempt was 0.67;(3)the standardized path coefficients for strain and psychiatric factors was 0.75,and the standardized path coefficients for psychiatric factors and suicide attempt was 0.30.4.5 Outcomes of individuals between high and low strain group8 cases of repeated suicide behavior appeared in the follow-up survey.Low strain group(score less than or equal 82)had 2 cases,of which 1 case was suicide attempt and 1 case was suicide death.High strain group(score above 82)had 6 cases,of which4 case were suicide attempts and 2 case were suicide deaths.Compared with the first survey,the score of self-esteem significantly declined in the low-strain suicide attempters(F=12.346,P=0.001),but increased in the high-strain suicide attempters(F=55.747,P<0.001)and controls F=52.916,P<0.001).The score of depression significantly declined in both low(F=72.542,P<0.001)and high(F=62.309,P<0.001)strain suicide attempters.The score of anxiety significantly increased in the low-strain suicide attempters(F=4.443,P=0.037),but declined in the high-strain suicide attempters(F=15.929,P<0.001)and controls(F=31.937,P<0.001).The score of social support significantly declined in the low-strain controls(F=11.151,P=0.001),but increased in the high-strain suicide attempters(F=9.694,P=0.002).5 Conclusions(1)Psychological Strain Scale includes four dimensions:value strain,aspiration strain,relative deprivation strain,and coping strain.The reliability and validity of total scale are acceptable.(2)Psychological strain is an important influence factor for suicide attempt in rural China.Male is more susceptible to strain than female.Male suicide attempt is mainly influenced by relative deprivation strain,but female suicide attempt is mainly influenced by value strain.Coping strain is a common risk factor of suicide for both male and female.(3)Social factors can affect suicide attempt directly,and also can affect suicide attempt indirectly by influencing the strain experiences.Strain not only can affect suicide attempt directly,but also can lead to suicide attempt by influencing individuals’ mental status.(4)Compared with low-strain individuals,high-strain individuals are more likely to have repeated suicidal behavior,especially for high-strain suicide attempters.But,the development of social and psychological condition in high-strain individuals isbetter.