Wincy S. C. Chan

Suicide in Hong Kong: a case-control psychological autopsy study

BACKGROUND The relative contribution of psychosocial and clinical risk factors to suicide among Chinese populations is an important issue. In Hong Kong, this issue requires vigorous examination in light of a 50% increase in suicide rate between 1997 and 2003. METHOD Using a case-control psychological autopsy method, 150 suicide deceased were compared with 150 living controls matched by age and gender. Semi-structured interviews were conducted with the next-of-kin of the subjects. Data were collected on a wide range of potential risk and protective factors, including demographic, life event, clinical and psychological variables. The relative contribution of these factors towards suicide was examined in a multiple logistic regression model. RESULTS Six factors were found to significantly and independently contribute to suicide: unemployment, indebtedness, being single, social support, psychiatric illness, and history of past attempts. CONCLUSIONS Both psychosocial and clinical factors are important in suicides in Hong Kong. They seem to have mediated suicide risk independently. In addition, socio-economic adversities seem to have played a relatively important role in the increasing suicide rate in Hong Kong.

On the modelling of nonlinear dynamic systems using support vector neural networks

Abstract Though neural networks have the ability to approximate nonlinear functions with arbitrary accuracy, good generalization results are obtained only if the structure of the network is suitably chosen. Therefore, selecting the ‘best’ structure of the neural networks is an important problem. Support vector neural networks (SVNN) are proposed in this paper, which can provide a solution to this problem. The structure of the SVNN is obtained by a constrained minimization for a given error bound similar to that in the support vector regression (SVR). After the structure is selected, its weights are computed by the linear least squares method, as it is a linear-in-weight network. Consequently, in contrast to the SVR, the output of the SVNN is unbiased. It is further shown here that the variance of the modelling error of the SVNN is bounded by the square of the given error bound in selecting its structure, and is smaller than that of the SVR. The performance of the SVNN is illustrated by a simulation example involving a benchmark nonlinear system.

Suicide among adults aged 30–49: A psychological autopsy study in Hong Kong

BackgroundA surge in suicide rates in middle age people in Hong Kong and many Asian countries was recently observed. However, there is a paucity of suicide research on this subgroup of people in Asia.MethodsThe next-of-kin of 85 suicide cases and 85 community subjects aged 30–49 years were interviewed by a psychological autopsy approach. Information was triangulated by interview notes, coroners court files, and police investigation reports.ResultsA multiple logistic regression analysis identified the following risk factors for suicide among the middle age people in Hong Kong: the presence of at least one psychiatric disorder (OR = 37.5, 95% CI 11.5–121.9, p < 0.001), indebtedness (OR = 9.4, 95% CI 2.2–40.8, p < 0.01), unemployment (OR = 4.8, 95% CI 1.3–17.5, p < 0.05), never married (OR = 4.2, 95% CI 1.1–16.3, p < 0.05), and lived alone (OR = 3.9, 95% CI 1.2–13.4, p < 0.05).ConclusionThe data show that socio-economical factors had a strong impact on suicide in the target group. Further research is needed to explore any positive qualities that protect the middle-aged from suicide. The prevention of suicide in the middle-aged requires multiple strategies.

A psychological autopsy study of pathological gamblers who died by suicide

BACKGROUND Pathological gambling is associated with suicidal ideation and attempt. There is no known report on pathological gambling preceding suicide. By examining a series of 17 suicide cases with evidence of pathological gambling prior to death, we sought to generate hypotheses for further study of this under-researched but rapidly-increasing worldwide public health problem. METHOD Psychological autopsy interviews using a semi-structured format were conducted with proxy respondents for suicide and control subjects aged 15-59 years in Hong Kong SAR, China. RESULTS Of the 150 suicides and 150 controls examined, 17 suicides (11.3%) and one control case (0.6%) met criteria for the diagnosis of pathological gambling at the time of death or interview. All 17 suicide cases with pathological gambling had unmanageable debt at the time of death. Fourteen cases (82.4%) had other associated psychiatric disorders, most often major depressive disorders (n=10, 58.9%) and substance-use disorders (n=3, 17.6%). None had ever received psychiatric treatment. LIMITATIONS Descriptive, retrospective case series with a small sample size. CONCLUSIONS Along with unmanageable debt, a high proportion of the suicide cases with pathological gambling also experienced other psychiatric illnesses, most often depression, at the time of death. None sought treatment for their addictive behavior or psychiatric illness prior to death. Pathological gambling is a modifiable risk factor for suicide for which means to enhance case identification and engagement in treatment are urgently needed. Clinicians treating depression should explore the presence of pathological gambling behavior or unmanageable debts among their patients. Addressing pathological gambling should be one important component of a comprehensive suicide prevention strategy especially in countries where gambling activities are legalized and expanding.

Suicide and unemployment: what are the missing links?

The suicide rate has been paralleled by an upward trend of unemployment in Hong Kong since 1997. This study aims to explore the unknown suicide-related factors among the unemployed. This information is useful in developing culturally specific suicide prevention initiatives related to unemployment. Seventy-six suicide deceased and 15 life subjects who were unemployed were selected from a previous psychological autopsy study. Logistic regression models were employed to estimate the relative suicide risks among the unemployed people. Among the unemployed, the suicide deceased were more likely to be male, had suffered from psychiatric illness, and had attempted suicide before. They also had acquired less competent social problem solving skills. Comparison with a small control group creates a generalizability problem. Suicide prevention for the unemployed could be done through mental health awareness programs; problem-solving skills training for attempters and males; and vocational training and job opportunities for discharged psychiatric patients and rehabilitees.

Population-Attributable Risk of Suicide Conferred by Axis I Psychiatric Diagnoses in a Hong Kong Chinese Population

OBJECTIVE This study was conducted to determine the population-attributable risk (PAR) of completed suicide among Hong Kong Chinese with axis I psychiatric diagnoses. METHODS With a case-control psychological autopsy method, 150 suicide decedents aged 15-59 were compared for axis I psychiatric diagnoses and psychosocial variables with 150 randomly selected age- and gender-matched persons living in the community. RESULTS In the presence of other, non-disease-related social risk factors (unemployment and unmanageable debt), past suicide attempt independently accounted for 44% of the PAR of suicide, followed by current major depressive disorder (27%), schizophrenia spectrum disorders (22%), and substance use disorder or pathological gambling (16%). Other diagnoses (such as anxiety and phobic disorders, dysthymia, adjustment disorders, and past major depressive episode) accounted for 24% of PAR. CONCLUSIONS Psychiatric morbidity remains the major risk factor for suicide in Hong Kong despite well-developed psychiatric services. Mental health policy should be refined to target clinical groups at high risk of suicide.

Online fault detection and isolation of nonlinear systems

This paper describes an online fault detection scheme for a class of nonlinear dynamic systems with modelling uncertainty and inaccessible states. Only the inputs and outputs of the system can be measured. The faults are assumed to be functions of the state, instead of the output and the input of the system. A nonlinear online approximator using dynamic recurrent neural network is utilised to monitor the faults in the system. The construction and the learning algorithm of the online approximator are presented. The stability, robustness and sensitivity of the fault detection scheme under certain assumptions are analysed. An example demonstrates the efficiency of the proposed fault detection scheme.

An Integrative Suicide Prevention Program for Visitor Charcoal Burning Suicide and Suicide Pact

An integrative suicide prevention program was implemented to tackle an outbreak of visitor charcoal burning suicides in Cheung Chau, an island in Hong Kong, in 2002. This study evaluated the effectiveness of the program. The numbers of visitor suicides reduced from 37 deaths in the 51 months prior to program implementation to 6 deaths in the 42 months post-implementation period. The number of visitor suicide pacts decreased from 7 pacts (15 individuals) to 1 pact (2 individuals). No statistically significant differences in the numbers of visitor suicide attempts and resident suicides were observed in the two time periods. No statistically significant changes in visitor suicides during the study period were observed on the comparison islands. The consistency and timing of reduction in visitor suicides correlated with the development and delivery of the integrative program on the intervention island, suggesting a causal association between program delivery and reduction of visitor suicides. The possibility of displacement seems small because there was no increase in visitor suicides on the comparison islands during the study period. This integrative approach in preventing target-specific suicides may serve as an example for other communities to develop suicide prevention programs that make use of the existing local resources.

What Can We Do to Help and Understand Survivors of Suicide in Hong Kong

Survivors of suicide or people bereaved by suicide are underresearched and underserviced. This report contains preliminary data, collected from a psychological autopsy study, which examines the characteristics of suicide survivors in Hong Kong. This paper considers the preliminary data currently available and attempts to suggest a way forward toward understanding and help for this underrecognized group of individuals in Hong Kong.

Suicide Notes in Hong Kong in 2000

Suicide notes have been regarded as one of the most informative data sources to understand the reasons why people commit suicide. However, there is a paucity of suicide note studies, leaving researchers with an assumption that this phenomenon remains static over time. This study examines this assumption by comparing the characteristics of note-leavers of the same population at 2 different points in time. The authors investigated the characteristics of 316 note-leavers in 2000 in Hong Kong and compared them to note-leavers in 1992. The proportion of people who left suicide notes increased from 20% to 35% between 1992 and 2000, a change that may be related to changes in suicide methods. Note-leavers in 2000 were characterized as individuals aged 25–59 years old, employed, with no physical illness, no psychiatric illness, and died as a result of charcoal-burning. Present data suggest that reasons for leaving suicide notes may have changed over the 8 years from 1992 to 2000.