Psychiatric comorbidity and its impact on mortality in patients who attempted suicide by paraquat poisoning during 2000-2010.
BACKGROUND
Paraquat poisoning is a lethal method of suicide used around the world. Although restricting its accessibility had been widely discussed, the underlying psychopathological mechanism of paraquat self-poisoning and its association with mortality have not yet been explicitly evaluated.


METHODS
We included all patients admitted to a tertiary general hospital in Taiwan between 2000 and 2010 following a suicide attempt by paraquat self-administration. Diagnoses were made upon psychiatric consultation based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria. The risk of mortality was calculated by logistic regression with various psychiatric or medical covariates.


RESULTS
The consultation-liaison psychiatry team assessed 157 patients who attempted suicide by paraquat poisoning. Mood disorders (54.0%), including dysthymic (26.7%) and major depressive disorders (24.7%), were the most common psychiatric diagnoses among the self-poisoning patients. Among those who attempted suicide, 87 patients (58.0%) died and dysthymic disorder (OR = 5.58, 95% CI: 1.13-27.69; p < 0.05) significantly increased the mortality risk after adjustment for relevant medical variables, including age, gender, severity index of paraquat poisoning (SIPP), and risk for respiratory failure.


CONCLUSIONS
Awareness of comorbid psychiatric illnesses, especially dysthymic disorder, is vital in the prevention and treatment of suicide by paraquat poisoning.
Department of Psychiatry, Chang Gung Memorial Hospital, Keelung branch, Keelung, Taiwan; Department of Psychiatry, Chang Gung Memorial Hospital, Linkou branch, Taoyuan, Taiwan.
Chemin
C
Lin
Department of Nephrology and Division of Clinical Toxicology, Chang Gung Memorial Hospital, Taipei, Taiwan; School of Medicine, Chang Gung University, Taoyuan, Taiwan.
Tzung-Hai
TH
Yen
Department of Psychiatry, Chang Gung Memorial Hospital, Linkou branch, Taoyuan, Taiwan; School of Medicine, Chang Gung University, Taoyuan, Taiwan.
Yeong-Yuh
YY
Juang
Department of Nephrology and Division of Clinical Toxicology, Chang Gung Memorial Hospital, Taipei, Taiwan; School of Medicine, Chang Gung University, Taoyuan, Taiwan.
Ja-Liang
JL
Lin
Department of Psychiatry, Chang Gung Memorial Hospital, Linkou branch, Taoyuan, Taiwan; School of Medicine, Chang Gung University, Taoyuan, Taiwan.
Shwu-Hua
SH
Lee
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis* / Q000523:psychology; D008875:Middle Aged; D010269:Paraquat / Q000506:poisoning*; D012720:Severity of Illness Index; D013405:Suicide / Q000523:psychology*; D013406:Suicide, Attempted / Q000523:psychology*; D011795:Surveys and Questionnaires; D013624:Taiwan; D055815:Young Adult
D010269:Paraquat