Prior Antidepressant Use May Affect Patients' Response to New Drugs — and Placebo
By Maia Szalavitz
@maiasz
March 20, 2012
+
Having previous experience with antidepressants can change a person's future response to both medications and to placebo, according to a new study. The findings could have implications for clinical trials designed to test new drugs.
For the new study, researchers led by Aimee Hunter, assistant professor of psychiatry at University of California, Los Angeles, studied the brain activity of 89 depressed adults who were enrolled in clinical trials of the antidepressant drug Prozac (fluoxetine) or Effexor (venlafaxine).
During the first week of each trial, all participants took placebo and then after that, they were given either a study drug or placebo. Using a technique called quantitative electroencephalography (QEEG), which involves a cap of electrodes placed painlessly on the scalp, researchers measured and mapped the participants' brain activity.
They found differences based on the participants' previous history of antidepressant use — a factor that wasn't taken into account in the trials. "We found that prior history affects the response to placebo," Hunter says. "If they had a prior history of taking antidepressants and were given placebo, the brain changes were indistinguishable from those of the people given medication."
Read more: http://healthland.time.com/2012/03/20/a-history-of-antidepressant-use-may-affect-patients-response-to-new-drugs-and-placebo/#ixzz1pgLqxGwo
By Maia Szalavitz
@maiasz
March 20, 2012
+
Having previous experience with antidepressants can change a person's future response to both medications and to placebo, according to a new study. The findings could have implications for clinical trials designed to test new drugs.
For the new study, researchers led by Aimee Hunter, assistant professor of psychiatry at University of California, Los Angeles, studied the brain activity of 89 depressed adults who were enrolled in clinical trials of the antidepressant drug Prozac (fluoxetine) or Effexor (venlafaxine).
During the first week of each trial, all participants took placebo and then after that, they were given either a study drug or placebo. Using a technique called quantitative electroencephalography (QEEG), which involves a cap of electrodes placed painlessly on the scalp, researchers measured and mapped the participants' brain activity.
They found differences based on the participants' previous history of antidepressant use — a factor that wasn't taken into account in the trials. "We found that prior history affects the response to placebo," Hunter says. "If they had a prior history of taking antidepressants and were given placebo, the brain changes were indistinguishable from those of the people given medication."
Read more: http://healthland.time.com/2012/03/20/a-history-of-antidepressant-use-may-affect-patients-response-to-new-drugs-and-placebo/#ixzz1pgLqxGwo
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