Suicide risk in patients treated with lithium.
BACKGROUND
Prior observational studies suggest that treatment with lithium may be associated with reduced risk of suicide in bipolar disorder. However, these studies are biased toward patients with the most severe disorders, and the relation to sex and age has seldom been investigated.


OBJECTIVE
To investigate whether treatment with lithium reduces the risk of suicide in a nationwide study.


METHODS
An observational cohort study with linkage of registers of all prescribed lithium and recorded suicides in Denmark during a period from January 1, 1995, to December 31, 1999.


METHODS
All patients treated with lithium in Denmark, ie, within community psychiatry, private specialist practice settings, and general practice.


METHODS
A total of 13 186 patients who purchased at least 1 prescription of lithium and 1.2 million subjects from the general population.


METHODS
All suicides identified on the basis of death certificates completed by doctors at the time of death.


RESULTS
Patients who purchased lithium had a higher rate of suicide than persons who did not purchase lithium. Purchasing lithium at least twice was associated with a 0.44 reduced rate of suicide (95% confidence interval, 0.28-0.70) compared with the rate when purchasing lithium only once. Further, the rate of suicide decreased with the number of prescriptions of lithium. There was no significant interaction between continued lithium treatment and sex and age regarding the suicide rate.


CONCLUSIONS
In a nationwide study including all patients treated with lithium, it was found that continued lithium treatment was associated with reduced suicide risk regardless of sex and age.
Kessing
Lars Vedel
LV
Department of Psychiatry, University Hospital of Copenhagen, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark. lars.kessing@rh.dk
Søndergård
Lars
L
Kvist
Kajsa
K
Andersen
Per Kragh
PK
D000328:Adult; D000367:Age Factors; D000368:Aged; D000928:Antidepressive Agents / Q000627:therapeutic use; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000188:drug therapy / Q000453:epidemiology / Q000401:mortality; D002423:Cause of Death; D003718:Denmark / Q000453:epidemiology; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D004359:Drug Therapy, Combination; D004363:Drug Utilization; D005260:Female; D006801:Humans; D008094:Lithium / Q000600:supply & distribution / Q000627:therapeutic use*; D008297:Male; D001523:Mental Disorders / Q000188:drug therapy / Q000453:epidemiology / Q000401:mortality; D008875:Middle Aged; D015995:Prevalence; D012042:Registries; D012307:Risk Factors; D012737:Sex Factors; D013405:Suicide / Q000523:psychology / Q000706:statistics & numerical data*; D000092864:Suicide Prevention
D000928:Antidepressive Agents; D014150:Antipsychotic Agents; D008094:Lithium