There were no significant differences between the 114 suicides and 91 deaths from other injuries by average age [21.3(sd=2.6) vs 20.9(2.6) years], time from death to interview [11.0(5.1) vs 11.0 (4.6) months], and total interview time [213(57) vs 205(64) minutes] (all p>0.05). There was, however, a significant difference in the average years of education [6.0(3.4) vs 7.0(2.7) years, p=0.03]. In the suicide and control groups 4.4% and 9.9%, respectively, were students.
Of the 114 suicides, 81.6% died by ingestion of poisons or medications, 12.3% by hanging, 3.5% by drowning, 0.9% by jumping, 0.9% by traffic accident, and 0.9% by gunshot. Among the 91 ingestion suicides for whom the agent was known, 63.7% took agricultural chemicals, 24.2% rat poisons, 4.4% medications, and 7.7% other poisons. In 61.8% (55/89) of the suicides by ingestion the poison or medication was stored, unlocked in the house or yard.
Among the suicides, 10.6% (12/113) drank alcohol just prior to the suicide; in 16.7% someone was present observing the suicidal act and in an additional 11.4% the victim immediately sought assistance after the act; 10.6% (12/113) wrote a will before the suicide and 19.3% left a suicide note; 27.4% (31/113) had discussed death with family members or other associates prior to the suicide; and 57.0% received medical resuscitation that failed.
The frequency of negative life events among the deceased in the year prior to death was much higher in cases than controls. The most frequent negative life events in the suicide group were loss of face or social embarrassment (43.0%), economic difficulties (33.3%), and conflict with parents (32.5%); while among the 90 control cases with detailed information about life events, the most frequent negative life events were love or engagement problems (27.8%), economic difficulties (23.3%) and long-term separation from family (15.6%). There were non-significant differences between cases and controls in the rates of being beaten by spouse, beaten by parents, and beaten or raped by others (in female: 13.0% vs. 0, 10.1% vs. 13.3%, and 7.2% vs. 0.0%; in males: 0.0% vs. 0, 8.9% vs. 2.7%, and 4.4% vs. 2.7%. Fisher’s exact test, all p>0.05).
Suicide decedents were much more likely to have experienced severe negative life events—typically intense interpersonal conflicts—in the two days before death: marital disputes (9.6%), disputes with parents (8.8%), disputes with other relatives (5.3%), being beaten by parents (4.4%), intense loss of face or social embarrassment (4.4%), being beaten by spouse (2.6%), and being beaten or raped by others (1.8%). In the control group, acute severe life events in the two days before death included being frightened (n=1), dissatisfaction with work or study status (n=1), being involved in a physical fight (n=1), conflict with mother in-law (n=1), and engagement problems (n=1).
Mental disorders were more common among suicides than among those who died of injuries (44.7% vs 11.1%). In the suicide group, the rates of the different psychiatric disorders were as follows: major depressive disorder (28.9%), schizophrenia (6.1%), borderline personality disorder (2.6%), mental retardation (1.8%), alcohol dependence (0.9%), substance abuse (0.9%), substance dependence (0.9%), brief psychotic disorder (0.9%), adjustment disorder (0.9%), mood disorder due to epilepsy (0.9%), psychotic disorder due to epilepsy (0.9%), and unspecified affective disorder (0.9%). Two of the 114 suicides met criteria for two mental disorders. Depressive symptoms of varying intensity and duration were present in 57.0% of the suicide decedents, but in many cases these symptoms were not severe enough or did not persist long enough to meet the criteria of a depressive disorder. Only 9.6% of all suicides and 21.6% of suicides with a diagnosable mental illness had ever seen a mental-health professional and only 7.9% and 17.6% had taken psychotropic medications in the month before death. In the 90 controls decedents for whom proxy informants completed the psychiatric examination, the rates of mental disorder were as follows: mental retardation (5.6%), schizophrenia (2.2%), alcohol dependence (1.1%), substance abuse (1.1%), and substance dependence (1.1%).
As shown in , compared with youth who died of other injuries, youth who died by suicide were more likely to be female and to live in rural villages. After adjusting for gender and location of residence there were no significant differences in the years of formal education, marital status, family financial status, having a pre-school age child or physical health status. The only demographic factors that remained significantly different between cases and controls were employment status (persons engaged in wage-earning jobs and students had lower risk of suicide than agricultural laborers, housewives and the unemployed) and whether or not the individual was functioning in his or her social role up until the time of death.
Comparison of demographic characteristics of suicides and deaths from other injuries in persons 15–24 years of age in China
The suicide and control groups differed significantly on a range of social and psychological factors. Most of these factors remained significantly different after adjustment for gender and location of residence (). Several risk factors for suicide had a clear dose-response effect: chronic stress score in the past year, increased acute stress at the time of death, and number of chronic negative life events (that lasted longer than one year). Living alone was not a risk factor for suicide. Having a prior suicide attempt was a strong risk factor for suicide but its adjusted OR could not be calculated because there were no prior suicide attempts in the control group. Though significantly more common in cases than in controls, only 44.7% (51/114) of suicide decedents had a diagnosable mental illness at the time of death; the prevalence of mental illness in female suicide decedents [37.7% (26/69)] was lower than in male suicide decedents [55.6% (25/45)] (Chi=3.53, df=1, p=0.061). Among the 63 suicide decedents without a diagnosable illness, 22 (34.9%) had sub-syndromal depressive symptoms and another 38 had moderate or severe levels of acute stress at the time of death.
Comparison of psychological, social environment, and life event characteristics of suicides and deaths from other injuries in persons 15–24 years of age in China
Multivariate models identified six independent risk factors for youth suicide: experiencing severe negative life events in the two days before death, the presence of any depressive symptoms in the two weeks before death, low quality of life in the month before death, higher acute stress at the time of death, female gender, and having a mental illness at the time of death ().
Multivariate model of risk factors for 15–24-year-old youth suicide in China comparing 114 suicides and 90 deaths from other injuries*
There is a significant interaction between gender and diagnosis (Wald z=5.80, p=0.016) so the presents stratified results for these variables. For the gender variable, among those without a diagnosis the risk of suicide is 54.6 times higher in women than men (p<0.001), but among those with a diagnosis the risk of suicide is not significantly related to gender (OR=1.3, p=0.837). Similarly, for the ‘met criteria of a psychiatric illness at time of death’ variable, among females the risk of suicide is, surprisingly, not significantly associated with diagnostic status (OR=0.3, p=0.361), but among males the risk of suicide is 14 times higher in those with a diagnosis (p=0.002). This indicates that females without a mental disorder and males with a mental disorder were at higher risk of suicide, so when counting the number of risk factors to which an individual is exposed gender and diagnostic status are combined into a single risk factor.
Among the 205 suicides and controls, the risk of suicide increases with exposure to an increasing number of risk factors: only 3.0% (2/67) of those unexposed to any risk factor or only exposed to 1 risk factor died of suicide, while 75.3% (73/97) exposed to 2 or 3 risk factors died of suicide, and 97.6% (40/41) exposed to 4 or 5 risk factors died of suicide. The suicide cases were exposed to an average (sd) of 3.16 (0.94) risk factors versus 0.95 (0.94) for controls (t=16.8, p<0.001); the average for females was 2.81 (1.00) versus 1.74 (1.52) for males (t=5.6, p<0.001).