Emory Researchers Find Paxil Improves Memory and Brain Structure In
Post-Traumatic Stress Disorder Sufferers
ATLANTA Emory University 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 J. Douglas Bremner, MD, associate professor
in the Department of Psychiatry and Behavioral Sciences and the Department
of Radiology at the Emory University School of Medicine, and Director
of Mental Health Research at the Atlanta Veteran's Affairs Medical Center.
Eric Vermetten, MD, former research fellow in the Emory Psychiatry Department
and now at the University of Utrecht in The Netherlands, was first author
of the study. The study, conducted over a 12-month period, was based
on 23 persons 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. In addition, PTSD patients suffer from problems
with new learning and memory as well as concentration," said Dr. Bremner.
"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 re-integrate and work through memories of their own
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 the state of Connecticut.
The patients took 10-50 mg of Paxil (average 20 mg), and were evaluated
at the end of 36 weeks. No psychotherapeutic 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 were also evaluated.
Patients in the study experienced significant improvement in verbal
declarative memory functions and retention, a four 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 study 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," added Dr. Bremner.
"This data provides clinicians with insight into the complicated nature
of treating PTSD, and the importance of effective treatments."
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, as many as 15 percent will develop
PTSD. Traumatic events can include car accidents, natural disasters,
physical or sexual assault, terrorist attack and robbery. 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.
Funding for the study was provided by GlaxoSmithKline, National Institute
of Mental Health and the National Center for PTSD. Co-authors include
Meena Vythilingam, MD and Dennis S. Charney, MD, Program for Mood and
Anxiety Disorders, National Institute of Mental Health; and Steven M.
Southwick, MD, Department of Psychiatry, Yale University School of Medicine.