Two antidepressants, Zoloft and Cipralex, work slightly better and are better tolerated compared with 10 other similar drugs for moderate to severe depression, a new review has found.

In Thursday's online issue of the medical journal The Lancet, an international team of doctors looked at more than 100 previous studies on antidepressants involving nearly 26,000 patients from 1991 to 2007. 

'If a patient is taking a drug and doing well, he should not stop and switch drugs.' — Study author Dr. Andrea Cipriani

They concluded that Zoloft, or sertraline, and  Cipralex, or escitalopram, were the best options when considering benefits, side-effects, and cost.

Edronax was considered the least effective.

"Such findings have enormous implications," wrote Dr. Sagar Parikh, a psychiatrist at the University of Toronto, in a commentary accompanying the study.

"Now a clinician can identify the four best treatments, identify individual side-effect profiles, explore costs and patients' preferences and collaborate in identifying the best treatment."

The study's authors weighed the drugs based on whether it reduced depression scores on two standardized tests by at least half and if patients had not stopped taking the medication in the last two months.

All of the antidepressants helped and there were no major differences, said the study's lead author, Dr. Andrea Cipriani of the University of Verona in Italy.

"If a patient is taking a drug and doing well, he should not stop and switch drugs," Cipriani said.

The other drugs reviewed were:

  • Celexa (citalopram)
  • Cymbalta (duloxetine)
  • Effexor (venlafaxine)
  • Ixel (milnacipran)
  • Luvox (fluvoxamine)
  •  Prozac (fluoxetine)
  •  Seroxat (paroxetine)
  •  Remeron (mirtazapine)
  • Zyban (bupropion)

Side-effects for the various drugs include nausea, sleeplessness, and sexual dysfunction.

The findings may lead doctors to prescribe Zoloft and Cipralex more often, but psychiatrists should also consider alternatives such as behavioural therapy, said Irving Kirsch, a professor of psychology at Britain's University of Hull.

The study was paid for by the authors' academic institutions in Britain, Greece, Italy, and Japan.

Cipriani has not received any grants from pharmaceutical companies. Several of his co-authors reported receiving funding from various makers of antidepressants.

With files from Associated Press