NEW YORK (Reuters Health) Aug 02 - Changes in EEG patterns during a placebo lead-in phase, which is often conducted before randomization to drug treatment in clinical trials, predict response to antidepressant therapy in patients with major depressive disorder, according to a report in the August issue of the American Journal of Psychiatry.
Previous studies have shown that changes in prefrontal EEG cordance after the start of antidepressant therapy are associated with clinical outcomes in patients with major depressive disorder, the authors explain.
Dr. Aimee M. Hunter and colleagues from UCLA Neuropsychiatric Institute examined the relationship between regional EEG changes (quantitative EEG theta cordance) during the 1-week placebo lead-in period and final clinical outcome among 51 depressed adults in two randomized, controlled trials of the antidepressants venlafaxine and fluoxetine.
Changes in prefrontal EEG cordance during the placebo lead-in phase were significantly associated with final Hamilton depression scale scores for patients randomized to one of the antidepressant medications, the authors report.
Decreases in prefrontal cordance were associated with lower final depression scores, the results indicate, and medication responders differed significantly from medication nonresponders.
To a similar extent, increases in right temporal cordance among patients who received placebo were associated with lower depression scores, the researchers note.
"Brain changes during the placebo lead-in phase may confound apparent medication effects associated with clinical outcomes in medication-treated subjects," the authors conclude.
The study findings suggest that "some neurophysiological changes that are associated with endpoint antidepressant outcome reflect nonpharmacodynamic factors."
"Future studies should examine how brain changes during the lead-in period may be associated with patient expectations, the therapeutic relationship, and treatment history," the investigators add.