The association between admission for poisoning with paracetamol or other weak analgesics and subsequent admission for psychiatric disorder: a Danish nationwide case-control study.
BACKGROUND
Many cases of paracetamol poisoning are with suicidal intent, but the association between paracetamol poisoning and subsequent psychiatric disorder is unknown.


OBJECTIVE
To examine the association between poisoning with paracetamol or other weak analgesics and subsequent psychiatric disorder.


METHODS
The study was set in a nested case-control design and based on nationwide Danish registers. We identified all patients diagnosed with schizophrenia, affective disorder or eating disorder in 1994-1998 and matched population controls. We estimated the relative risk of these psychiatric disorders after admission for paracetamol or nonparacetamol poisoning, adjusting for income, employment and marital status.


RESULTS
We included 12,603 cases with psychiatric disorder, and 1.2% had a diagnosis of poisoning compared with 0.2% of the 252,060 matched population controls. Compared with those with no diagnoses of weak analgesic poisoning, the risk of schizophrenia increased 3.9-fold after paracetamol poisoning, and 2.0-fold after nonparacetamol poisoning. The risk of affective disorder increased 12.2-fold after paracetamol poisoning and 2.6-fold after nonparacetamol poisoning. The risk of eating disorder increased 5.0-fold after paracetamol poisoning, and 2.2-fold after nonparacetamol poisoning. The risk of a diagnosis of psychiatric disorder was very high immediately after poisoning and remained increased for more than 10 years.


CONCLUSIONS
Paracetamol poisoning is a strong risk marker for psychiatric disorder, particularly affective disorders.
Jepsen
P
P
Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark. pj@dce.au.dk
Qin
P
P
Nørgård
B
B
Agerbo
E
E
Mortensen
P B
PB
Vilstrup
H
H
Sørensen
H T
HT
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000700:Analgesics / Q000506:poisoning*; D016022:Case-Control Studies; D002648:Child; D003718:Denmark / Q000453:epidemiology; D062787:Drug Overdose / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology*; D008875:Middle Aged; D012307:Risk Factors
D000700:Analgesics