Not all people with depression are eligible to take part in medical trials. Some people are excluded from phase III trials which compare drugs against a placebo because they have milder depression (which may be more likely to respond to a placebo effect), or because they have chronic depression, other mental-health problems or physical illnesses. Researchers from the University of Pittsburgh Graduate School of Public Health compared the effects of treatment on people who did, or did not, meet the criteria for phase III trials. Of 2,855 patients being treated with citalopram fewer than one in four (22.2%) met the inclusion criteria. People who met the criteria for the trials were more likely to get better and had less severe side effects suggesting that reports about the effectiveness of antidepressants might not be as encouraging in the 'real world.'
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