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Whether
or not a patient experiences side effects from antidepressant drugs
may be predicted by brain activity prior to treatment, says a UCLA
study that's the first to show a link between brain function
and medication side effects.
The study compared brain function changes in 32 healthy individuals
with no history of depression who took either an antidepressant
(venlafaxine) or a placebo for four weeks. Individuals without depression
were chosen so that their brain function would not be affected by
the illness. All participants took a placebo pill for one week before
being randomly assigned to either group.
During the seven check points that occurred during the study, a
research nurse asked participants whether they experienced side
effects such as gastrointestinal upset, cardiovascular disturbance,
sleep disturbance, anxiety and agitation.
It was found that changes in brain function in the prefrontal region
during the one-week placebo period were related to side effects
in those who received antidepressants. Specifically, changes in
prefrontal brain function before the start of the medication signaled
a greater number of adverse effects from the antidepressant. The
changes were monitored by "cordance," a quantitative electroencephalography
(QEEG) imaging technique.
Several factors can affect a patient's vulnerability to antidepressant
side effects including the medication itself and patient expectations.
The researchers hope the findings will allow a new way to determine
whether an individual is susceptible to antidepressant side effects
and ultimately improve treatment.
Neuropsychopharmacology
April 2005, Vol. 30, Number 4: 792-799
Medical
News Today March 31, 2005
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