Emory researchers have found that paroxetine HCL
(Paxil) produces measurable improvement in verbal memory and also
increases the size of the hippocampus, a key area of the brain involved
in learning and remembering, in persons suffering from post-traumatic
stress disorder (PTSD).
Their study, which will be published in the Oct. 1 edition of Biological
Psychiatry, also found that Paxil significantly reduces the three
main symptom clusters of PTSD: re-experiencing the traumatic event;
avoidance and emotional numbing related to experiences that recall
the traumatic event; and hyperarousal at inappropriate times.
The study was directed by Douglas Bremner, associate professor of
psychiatry and behavioral sciences and director of mental health
research at the V.A. Medical Center. Eric Vermetten, former research
fellow psychiatry and now at the University of Utrecht in The Nether-lands,
was first author. Conducted over a 12-month period, the study examined
23 people who suffered with PTSD from a variety of causes, most
commonly childhood abuse.
“Many patients with post-traumatic stress disorder suffer
impaired memory, often leading them to experience distorted or fragmented
memories of the traumatic event,” Bremner said. “In
addition, PTSD patients suffer from problems with new learning and
memory as well as concentration. The findings of this study indicate
that Paxil may help reverse memory loss and increase hippocampal
volume, leading to clinically significant improvements in memory
and concentration that will improve their work and social function.
It may also be true that improved memory will help trauma survivors
reintegrate and work through memories of their own traumatic events.”
Previous studies have demonstrated that patients with PTSD suffer
a decrease in volume of the hippocampus, as well as deficits in
hippocampal-based learning and memory as measured with neuropsychological
testing. Some studies have associated high levels of cortisol, a
hormone that regulates stress, with negative effects on this area
of the brain. Studies in animals have also shown that medications
such as Paxil have a beneficial effect on the growth and structure
of hippocampal neurons.
The study participants were all residents of Connecticut. The patients
took 10–50 mg of Paxil (average 20 mg) and were evaluated
at the end of 36 weeks. No psycho-therapeutic procedure was administered
in the study phase, except for supportive therapy. Hippocampal volume
was assessed by MRI before and after treatment. Stress parameters
and measures of declarative memory function also were evaluated.
Patients in the study experienced significant improvement in verbal
declarative memory functions and retention; a 4 percent increase
in the right hippocampus, which affects visual/spatial functioning,
and a 5.2 percent increase in their left hippocampus, which controls
verbal functioning; decreased cortisol levels, a stress regulator,
in the brain; and significant relief of each of the three major
symptom clusters of PTSD.
“These findings reinforce that post-traumatic stress disorder
is caused by biologic changes in the brain, and that medications
like Paxil play a neurobiologic role in its treatment,” Bremner
said. “This data provides clinicians with insight into the
complicated nature of treating PTSD, and the importance of effective
Affecting up to 16 million Americans, PTSD is a debilitating condition
that develops after experiencing or witnessing a traumatic event.
Of people exposed to traumatic events—such as car accidents,
natural disasters, physical or sexual assault,
terrorist attack and robbery—as many as 15 percent will develop
PTSD. To be diagnosed with PTSD, people must experience intense
fear, helplessness or horror and experience each of the three main
symptom clusters for more than one month post-exposure to the trauma.