But earlier this year it was discovered the drug increases the risk of suicide. Now a new trial has found the drug almost trebles the chances of depression or anxiety.
At the moment the drug is available only in the UK, where it sailed through the approval process last year. But it was researchers in the US who discovered the original suicide risk, which they uncovered while they were considering the drug's safety before granting it approval for the American market.
Now researchers in Denmark have analysed four studies into the drug, and have uncovered the increased risk of depression and anxiety. The depression was often so bad that the patient stopped treatment.
(Source: The Lancet, 2007; 370: 1706-13).