But there are some caveats. It should first be noted that this was not was not a randomly-assigned, placebo-blind study, the gold standard in gauging how effective treatments are, said Dr. Philip Janicak, at Rush University, who wasn't involved in the research. Rather, it compared two different groups of patients. The first group consisted of 307 patients who were treated with TMS at 42 clinics throughout the U.S., after failing to respond to drugs. The second group, or rather second pool of data, was taken from a previous nationwide study, completed in 2006, of patients who were given new antidepressant medications after failing to respond to previous drug therapy. The patients in the latter group were chosen to match the former group as closely as possible, on measures such as sex, age, severity of illness, etc.