All antidepressant drugs are not created equal, according to the authors of one of the few studies that have ever systematically analyzed and compared "new generation" medicines for treating depression. 

What qualities are important in an anti-depressant? Efficacy? Tolerance? Side effects? Cost? 

In the analysis of 12 drugs, two came out on top as the most effective and best tolerated as first-line treatments: sertraline (Zoloft) and escitalopram (Lexapro). Venlafaxine (Effexor) and mirtazapine (Remeron) rounded out the top four for effectiveness, but venlafaxine was also among the four drugs patients were most likely to quit taking because of side effects. Reboxetine (Edronax) was less effective than the rest. 

While psychiatrists treating depressed patients every day have had a sense of which medications are best, the current study "nails it," says Sagar V. Parikh, M.D., of the University of Toronto. Parikh, who wrote a comment accompanying the study that is published in the current issue of The Lancet, says the findings have "enormous implications" because, for the first time, they offer doctors an evidence-based, unbiased way to recommend treatment. And, he adds, they give patients a "gold standard of reliable information," especially since the study's authors plan to make their findings available free on the Web. 

Not so fast, says Gerald Gartlehner, M.D., M.P.H., who coauthored a review of the benefits and risks of the same 12 drugs published last November in the Annals of Internal Medicine. He and his colleagues concluded, based on their review done while Gartlehner was at the RTI-UNC Evidence-Based Practice Center in Chapel Hill, North Carolina., that there was no clinically meaningful evidence that any one of the drugs was better than the rest. Instead, they argued, decisions on which drug to use should be based on factors such as cost and side effects. 
Were they all found to be equally effective?
In the analysis of 12 drugs, two came out on top as the most effective