The mood-stabilising drug lithium reduces suicide risk by more than 60 percent among people with depression, a study said Thursday.
Lithium has long been prescribed to treat unipolar disorder (also called clinical depression) and bipolar disorder (manic depression) -- but its use has been declining in many countries, according to Andrea Cipriani, who co-wrote the paper in the online journal bmj.com
"One reason for the decline in lithium use might be that it has a reputation among psychiatrists as a toxic drug that is difficult to use," the Oxford University psychiatry lecturer told AFP by email.
Doctors have to continuously monitor the lithium blood levels of patients to prevent an overdose, the symptoms of which include dizziness, seizures or heart problems.
Lithium has also been associated with a higher risk of kidney and thyroid problems and weight gain.
But the new research suggests it still has an important place as a depression treatment.
It reduced the risk of death or suicide by 62 percent on average, according to the paper that reviewed the findings of 48 drug trials involving nearly 7,000 patients between 1968 and 2013.
Measured for suicide alone, the risk was reduced by 87 percent on average, said Sirianian -- adding there was no increase in deaths linked to lithium overdose.
The trials had measured the effects of lithium compared to either placebo or alternative active drugs on people with depression -- who have a 30-times greater risk of suicide than the general population.
"This updated systematic review reinforces lithium as an effective agent to reduce the risk of suicide in people with mood disorders" -- both unipolar and bipolar, the study authors wrote.
The effect may be ascribed to lithium "decreasing aggression and possibile impulsivity", added a statement.
The authors said mood disorders were a leading cause of global disability, affecting one in three Americans in their lifetime.