| Quantitative
electroencephalograms may predict success of antidepressant therapy Changes in frontal cortex activity detected with quantitative electroencephalography can predict the effectiveness of an antidepressant medication within days of initiation of treatment and weeks before there is a clinical response, according to an article in the July issue Neuropsychopharmacology. The new findings could lead to treatment programs that help patients with depression feel better more quickly by decreasing the evaluation period from weeks to days. "Up to 40 percent of depressed patients do not respond to the first medication they try. Since it takes several weeks for an effective treatment to produce clear improvement, doctors often wait 6 to 12 weeks to decide that a particular medication just isn't right for that patient and move on to another treatment," said Dr. Ian A. Cook, lead author of the study. "By comparing electroencephalogram (EEG) measurements before treatment with those soon after treatment begins, doctors may be able to evaluate the usefulness of an antidepressant within days rather than having to wait weeks-to-months," Cook said. "This technique also could slash the time and costs needed to develop and research new antidepressants." The study examined 51 adult patients diagnosed with acute depression. Each participated in one of two double-blind, randomized treatment trials. One group received fluoxetine or placebo. The other received venlafaxine or placebo. Each subject received a quantitative electroencephalogram prior to initiation of treatment, 48 hours after treatment, and one week after treatment. Of the 25 subjects given active medication, 13 (52 percent) responded positively. Of the 26 subjects given placebo, 10 (38 percent) responded. Subjects who responded to medication uniquely showed significant decreases in cordance, a measure of brain wave activity, at 48 hours and one week. Clinical changes did not begin to emerge until after four weeks. Subjects with the greatest measured changes in cordance had the most complete response to the medication after eight weeks. "Other researchers have compared brain scans of depressed people before and after treatment and found differences between those who recovered and those who did not respond. Those findings, however, do not allow prediction of whether a particular patient is likely to get well," said Cook. "This is the first study to detect specific changes in brain wave activity that precede the clinical changes in a way that can usefully predict response." Current research is aimed toward
determining whether the same pattern holds for other antidepressant
medications; the investigators are also working to simplify the
method to make it easier to use in the clinical setting.
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