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y 30 (2008) 561–563

General Hospital Psychiatr

Clinical predictors of psychiatric and medical morbidities ofcharcoal-burning suicide attempt in Hong Kong

Edwin Lee, M.Sc., M.B.Ch.B., M.R.C.Psych.⁎,Chi-Ming Leung, M.B.B.S., M.R.C.Psych., F.H.K.C.Psych., F.H.K.A.M.

Department of Psychiatry, The Chinese University of Hong Kong, Hong Kong SAR, Hong Kong

Received 14 July 2008; accepted 2 September 2008

Abstract

Objective: This naturalistic retrospective cohort study explored the demographic and clinical factors associated with psychiatric and medicalmorbidities among patients with suicide attempts by burning charcoal.Method: We conducted a follow-up study of 69 cases with charcoal-burning suicide attempts in two general hospitals. The associationsbetween demographic, clinical characteristics and outcomes were analyzed.Results: The presence of past psychiatric treatment, past history of suicide attempt and physical complications were associated with theoccurrence of psychiatric morbidity after the index suicide attempt. Loss of consciousness and abnormal blood acidity were associated withmedical morbidity after the index admission.Conclusion: Psychiatric and medical morbidities are common among charcoal-burning suicide attempts and identified clinical factorsassociated with these problems may be useful in its management.© 2008 Elsevier Inc. All rights reserved.

Keywords: Charcoal; Suicide; Psychiatric; Medical; Morbidity

1. Introduction

Suicide remains a great burden in the 21st century rangingfrom individual to socio-economical level [1]. An increasingtrend in suicide rate was noted in Hong Kong in recent years[2]. Charcoal-burning suicide has an exponential increasefrom 1.8% of all suicide deaths in 1998 to 25.6% of allsuicide deaths in 2003 in Hong Kong [3]. The substitutioneffect of charcoal burning to other causes of death is minimal[3]. This second most common suicide method was found tobe different from suicide by other means, e.g., people beingmore economically active, physically healthy and less likelyto have preexisting mental illness [4]. It can cause physicaland neurological complications like burn, rhabdomyolysisand cognitive impairment, which can be serious anddisabling [5]. Psychiatrists are commonly involved inassessment of risk and psychiatric co-morbidity. There are

⁎ Corresponding author. Tel.: +852 2607 6035.E-mail address: elee@cuhk.edu.hk (E. Lee).

0163-8343/$ – see front matter © 2008 Elsevier Inc. All rights reserved.doi:10.1016/j.genhosppsych.2008.09.001

limited studies on the assessment of patients with charcoal-burning suicide attempts. We conducted a naturalisticretrospective cohort study to explore demographic andclinical factors associated with different psychiatric andphysical morbidities.

2. Method

We conducted a naturalistic retrospective cohort study intwo general hospitals in Hong Kong. The case records from apsychiatric consultation liaison team from February 2003 toApril 2005 were reviewed. All patients who were admittedbecause of suicide-related behaviours by burning charcoalwith some degree of suicidal intent with or without injurieswere recruited [6]. For each subjects, the general demo-graphic data including sex, age, marital status, livingcondition and occupation were extracted. The clinical dataincluding past history of suicide, past psychiatric history,conscious state, carboxyhaemoglobin level and pH value onadmission were collected. The reason for the suicide attemptwas determined from the case record by two investigators.

562 E. Lee, C.-M. Leung / General Hospital Psychiatry 30 (2008) 561–563

Outcome variables including psychiatric and medicalmorbidities after the index admission were searched in theperiod from the event to the study period. Ethical approvalwas obtained from local human research ethics committee.

The characteristics of cases of charcoal-burning suicidewere summarized using descriptive statistics. The associa-tions between demographic, clinical characteristics andoutcomes were analyzed by Spearman's correlation coeffi-cients. The Statistical Package for the Social Sciences forWindows version 13.0 was used.

3. Results

There were 69 patients with suicide attempts by burningcharcoal collected from February 2003 to April 2005.Among these patients, 38 (55%) were male and 31 (45%)were female. The mean age was 36.9 years with a standarddeviation of 10.1 years (range 22–58 years). For the maritalstatus, 32 (46%) were married, 30 (44%) were single and7 (10%) were divorced. There were 53 (77%) patients livingwith others and 16 (23%) patients living alone.

There were 27 (39%) patients who had loss ofconsciousness upon admission. Concerning the physicalinvestigations on arrival of hospital, the mean carboxyhae-moglobin level was 23.7% with a standard deviation of14.8%. The mean pH level was 7.40±0.06 (normal range7.35–7.45). Abnormal pH value was present in 20 (29%)patients. Past history of suicide attempt was found in 23(33%) patients and 16 (23%) patients had past psychiatrictreatment. There were 38 (55%) patients who had con-comitant drug poisoning and 21 (30%) patients who had asuicide attempt because of financial reasons.

Psychiatric morbidity was found to be present in 26 (38%)patients. Among those who had psychiatric morbidity, 20(77%) cases were diagnosed to meet the criteria fordepression. Other diagnoses include schizophrenia, delu-sional disorder and personality disorder. Medical morbiditywas present in 15 (22%) cases. It ranged from differentdegrees of burn injury to severe rhabdomyolysis, and themost severe case died because of complications.

The presence of past suicide attempt and past psychiatrictreatment were significant factors correlated with thepresence of psychiatric morbidity after the event (r=0.338and 0.707, respectively, with Pb.01). The presence ofphysical complications is associated with the presence ofpsychiatric morbidity with r=0.243 (Pb.05). The presenceof loss of consciousness and an abnormal pH value weresignificant factors correlated with the occurrence of medicalmorbidity after admission (r=0.513 and 0.360, respectively,with Pb.01).

4. Discussion

Charcoal burning has become a common method ofsuicide in Hong Kong since its first report [7]. The increasing

trend of this suicide method raised our concern to learn moreabout its effect on our patients [8]. Psychiatrists areincreasingly involved since the assessment of suicide riskis important for clinical decision making and treatment [9].Research on charcoal-burning suicide is growing, but thiswas one of the few which investigated factors associatedwith medical and psychiatric comorbidity. We demonstratedthat past psychiatric treatment, past suicide attempt andphysical complications were associated with the presence ofpsychiatric morbidity despite the uncommon history ofmental illness.

Patients may present with different symptoms aftersuicide attempt by burning charcoal. In the acute phase,patients may suffer from effects of carbon monoxidepoisoning. The brain and the heart are sensitive to hypoxicinjury because of their high metabolic rate. Patients maypresent with different symptoms including headache, dizzi-ness, weakness, shortness of breath, chest pain, confusion,convulsion and coma. Information on the patient's carbox-yhemoglobin level and duration of exposure are importantfor estimation of the severity of carbon monoxide poisoning.Laboratory carbon monoxide oximetry can assess the arterialoxygenation accurately by distinguishing oxyhemoglobinfrom carboxyhemoglobin. Noninvasive pulse carbon mon-oxide oximeter may also be useful. Monitoring of cardiacfunction by electrocardiogram, cardiac enzymes and echo-cardiogram can detect the extent of cardiac muscle damagedue to tissue hypoxia. High-flow (100%) oxygen should beused in patients with carbon monoxide poisoning, despitenormal pulse oximetry readings. Although immediatenormobaric oxygen therapy may be an adequate treatmentfor some cases, hyperbaric oxygen therapy may beconsidered with balance of costs and risks of transport forhyperbaric oxygen treatment.

Psychiatrists may also be involved for management ofpsychiatric symptoms in addition to the suicide attempt.Hypoxic brain damage predominates in the cerebral cortex,cerebral white matter and basal ganglia, especially in theglobus pallidus. Subsequently, only symptomatic therapy isavailable for the long-term sequelae of CO poisoning.Neuropsychiatric symptoms such as personality changes,psychosis and cognitive deficit and parkinsonism may occurin patients from 3 days to 240 days after the incident [10].Formal neuropsychological testing and follow-up may helpto delineate the extent of damage secondary to carbonmonoxide encephalopathy.

There are several limitations that deserve discussion.First, this is a retrospective cohort study, which involvespatients from two hospitals in Hong Kong in 2004 only.Careful interpretation of results is needed before general-ization of the findings on charcoal burning suicide attempts.Second, people who died of burning charcoal were notcompared. Third, the data were retrieved from case records,which may limit the detail of information available. Fourth,the association with the number of previous suicidal attemptswas not studied.

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Despite the limitations, this study explored the factorsassociated with psychiatric and medical morbidities inpatients with charcoal burning suicide attempts. The studyincreases the understanding of this recently evolved, yetcontagious suicide method in Asia [11]. The Hong Kongcommunity has started education and regulation of access tocharcoal. Future study is being planned to explore the riskfactors and assess the usefulness of prevention strategies.

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