| BackgroundAttempted suicide is defined as the behavior of having taken action to hurt oneself, but not died successfully. Each year approximately1million people commit suicide, at least10million commit attempted suicide. According to the statistics of China’s Ministry of Health, each year approximately250,000people commit suicide, at least2million commit attempted suicide in China. Attempted suicide is the most reliable predictor of suicide.30%to60%of suicides have attempted suicide history, and10%to14%of suicide attempters would commit suicide successfully. The suicide risk of suicide attempters is100times greater than that of general population. Therefore, to research the risk factors of attempted suicide is significant for suicide prevention.Many factors, such as society, biology, mental and psychology, can result in attempted suicide. Most attempted suicide is impulsive and closely related to life events in China. However, negative life events are often difficult to be predicted and intervened. Even facing the same life events, different people have different reaction. According to the explanation of stress-susceptibility model, acute stress events as the trigger, combined with some individual susceptible factors result in suicide. The individual susceptible factors include disease, psychology, personality, family, and community environment, et al. Personality traits as the long-term stable factors, are very important factors to adjust suicide behavior. Impulsivity would lead to suicide has been testified. However, studies on association between self-esteem, anxiety and suicide are few and the results are inconsistent in China. In addition, it is unclear about how personality traits affect suicide behavior in negative life events, depression and attempted suicide. Consequently, in this study, we try to build a model among self-esteem, anxiety, depression and attempted suicide and explore the effect of different personality traits on suicide. Classification tree analysis was performed to find high-risk characteristics of attempted suicide, so as to provide effective reference for suicide prevention and intervention.Objectives1. To investigate epidemiological characteristics of attempted suicide in rural population of Shandong Province.2. To discuss the association between self-esteem, anxiety and attempted suicide and explore the function of personality traits on the chain reaction of negative life events, depression and attempted suicide. This will provide new evidence for model of stress-susceptibility.3. To explore high-risk characteristics clusters of attempted suicides among rural population in China, and to serve as effective reference to frame strategies for suicide prevention and intervention.Methods1. SubjectsSix counties, in disease surveillance points of Shandong Province, were selected, and rural residents aged15-70years old who commit attempted suicide during the period from October1st,2009to March31st,2011, were consecutively sampled. Meanwhile, the controls with same gender, age (no more than3years), and without suicide history, were random sampled in same district.2. InstrumentsAll data were collected by face to face interviews. The instruments include Suicide Intent Scale (SIS), Self-Esteem Scale (SES), Trait Anxiety Inventory (TAI), Interview for Recent Life Events (IRLE), Center for Epidemiologic Studies Depression Scale (CES-D) and Structured Clinical Interview for DSM-IV Axis I Disorders,2001, Research Version.3. Statistical methods The data were analyzed by software of SPSS16.0, SAS9.1and AMOS7.0. Chi-square test, t-test, ANOVA, linear correlation, univariate conditional logistic regression and multivariate conditional logistic regression were used to analyze the association between self-esteem, anxiety and attempted suicide. Structural equation model of self-esteem, anxiety and attempted suicide was built to explore the role of personality traits in negative life events, depression and attempted suicide. Classification tree analysis was employed to determine the risk factors of attempted suicide and high risk populations related to it.Main results1. The epidemiological characteristics of attempted suicide409suicide attempters were investigated in this study, in which the male attempted suicides were132(32.3%), the female were277cases (67.7%), and the male/female ratio was1:2.1. The average age of attempted suicides was43.90±13.32years old. Suicide seasons for suicide attempters were mainly in summer (33.1%) and spring (29.5%).70.4%cases committed attempted suicide on daytime (8:00-20:00). There were no statistical significant differences between male and female in seasons (x2=1.781, P=0.619) and times (12=3.114, P=0.374).354cases (86.6%) were found at home.334cases (84.1%) took pesticide.36cases (8.8%) had attempted suicide history. There were no statistical significant differences between male and female in attempted suicide location (x2=1.735, P=0.188), methods (x2=8.528, P=0.227) and attempted suicide history (x2=1.218, P=0.968). Suicide attempters had low suicidal intention and the mean score of it, in which items4and8were deleted, was2.81±2.34(male vs. female, t=0.951, P=0.342). Interpersonal conflict, pressure of life and physical diseases were accumulatively amount for83.1%of the reason of attempted suicide. There was statistical difference between male and female (x2-33.535, P<0.001). Compared with male, the female took up higher proportion in interpersonal conflict, however the proportion of pressure life was lower.2. Association between self-esteem, anxiety and attempted suicideExcept for item5, the reliability of Self-Esteem Scale (Rosenberg) was high (the Cronbach’s a of suicide attempters and controls were0.885and0.839, respectively). The exploratory factor analyses showed that except for item3and8, others were in accordance with original scale design. Univariate conditional logistic regression showed that there was a negative correlation between self-esteem and attempted suicide (OR=0.302,95%CI=0.223-0.409), and multivariate conditional logistic regression showed that, comparing with low level of self-esteem, the odds ratio of high level of self-esteem was0.697(95%CI=0.418-0.970). All of above confirmed that self-esteem was a protective factor for attempted suicide.State-Trait Anxiety Inventory (Spielberger) showed well reliability in this study (the Cronbach’s a of suicide attempters and controls were0.903and0.852, respectively) except for item18. The exploratory factor analysis was carried out in suicidal group and control group, and3factors and5factors were yielded, which were different from the hypothesis of the scale’s original design. Univariate conditional logistic regression showed that there was a positive correlation between anxiety and attempted suicide (OR=4.567,95%CI=3.200-6.518), and multivariate conditional logistic regression showed that, comparing with low level of anxiety, the odds ratio of high level of anxiety was2.454(95%CI=1.527-3.944). All of above confirmed that anxiety was a risk factor for attempted suicide. In the model of negative life events, self-esteem, trait anxiety, depression and attempted suicide, self-esteem and anxiety didn’t influenced attempted suicide directly and only depression affect attempted suicide directly. Self-esteem and anxiety was negative correlation and could influence attempted suicide through depression indirectly. Self-esteem and trait anxiety could moderate the effect of negative life events to attempted suicide. The effect of negative life events attempted suicide would reduce as the level of self-esteem increases and trait anxiety decreases.3. Characteristic cluster analyses of attempted suicideHigh-risk characteristic clusters of suicide attempters in Shandong Province mainly were:①depression and negative life events;②depression and no negative life events;③no depression and negative life events;④no depression, no negative life events, low self-esteem and high anxiety. Sensitivity of the attempted suicide classification tree in training sample was77.13%, while the specificity was87.32%. In test sample, the sensitivity was72.85%while the specificity was83.33%. The sensitivity and specificity of training and test sample consistently showed that the attempted suicide classification tree discriminated well.Conclusions and Suggestions1. Conclusions(1) People tended to commit suicide at home, in summer, spring, daytime, and by taking poison. Interpersonal conflict was the main reason for attempted suicide, and attempted suicide had a low suicidal intention.(2) Self-esteem was a protective factor and anxiety was a risk factor for attempted suicide, however, both of them didn’t influenced attempted suicide directly. Self-esteem and anxiety was negative correlation and could influence attempted suicide through depression indirectly. Self-esteem and anxiety could moderate the effect of negative life events to attempted suicide. The effect of negative life events attempted suicide would reduce as the level of self-esteem increases and trait anxiety decreases.(3) High-risk characteristic clusters of suicide attempters in Shandong Province mainly were:①depression and negative life events;②depression and no negative life events;③no depression and negative life events;④no depression, no negative life events, low self-esteem and high anxiety.2. Suggestions(1) Most suicide attempters in Shandong Province were mainly by ingestion of pesticide, the accessibility of pesticide provided possibility. Therefore, controlling the feasibility of pesticides and prohibiting of high toxic pesticides will probably reduce the suicide rate significantly.(2) Suicide can be prevented. Self-esteem and anxiety, as the stable personality traits, could moderate suicide. So we should pay attention to the people with low self-esteem and high anxiety and give them more social support.(3) In future suicide prevention, the identification ability of high risk population should be improved and corresponding screening and assessment tools should be developped. Then individuals at high risk can be better identified and prevented. |
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