Posttraumatic stress disorder occurs in patients who have experienced, witnessed or have
been confronted with an event involving actual death or the threat of death, serious injury,
or the threat to physical health and felt fear, helplessness, or horror. As a result,
patients continue to re-experience, recollect, dream, or have flashbacks about the traumatic
Research on PTSD continues to show metabolic changes in specific areas of the brain in
patients diagnosed with PTSD. For example, neuroimaging studies (functional MRI and PET
scans) reveal that blood flow and glucose utilization increases in the right frontal,
limbic, and paralimbic areas of the brain in patients with PTSD, particularly when they are
recalling the traumatic event associated with their symptoms.
One potential method for interfering with the neuronal circuitry associated with traumatic
memories is through the use of repetitive transcranial magnetic stimulation (rTMS). This
technique involves the placement of a cooled electromagnet with a figure-eight coil on the
patient's scalp and rapidly turning on and off the magnetic flux. This permits
non-invasive, relatively localized stimulation of the surface of the brain (cerebral
cortex). The effect of magnetic stimulation varies, depending upon the location, intensity
and frequency of the magnetic pulses. Preliminary clinical data shows that low frequency
rTMS stimulation leads to a decrease in regional cerebral blood flow.
This study is designed to determine if rTMS stimulation in patients diagnosed with PTSD
leads to symptomatic improvement, reductions in blood flow to specific areas of the brain,
and improvements in the regulation of the autonomic nervous system.
A growing body of data indicates that patients with posttraumatic stress disorder (PTSD)
have regionally selective alterations in brain metabolism and processing of information.
For example, neuroimaging studies reveal increased blood flow and glucose utilization in
right frontal, limbic and paralimibic brain structures in patients with PTSD, particularly
when they are recalling the traumatic event associated with their symptoms. These
alterations in regional brain activity are thought to be related, in part, to the
distressing emotional symptoms associated with traumatic memories. Autonomic Nervous System
(ANS) dysregulation is common in PTSD, with sympathetic hyper-reactivity and relative lack
of parasympathetic modulation. In addition, abnormalities in hormone levels such as thyroid
hormones and the hypothalmic-pituitary-adrenal axis have been demonstrated. Repetitive
transcranial magnetic stimulation may provide a non-invasive technique for normalizing the
alterations in regional brain metabolism, possibly leading to improvements in PTSD symptoms
and concomitant improvement in ANS and hormonal balance. In particular, preliminary
clinical data indicate that low frequency (i.e., approximately 0.9-1 Hz) rTMS stimulation
leads to a decrease in regional cerebral blood flow. The purpose of the present study is to
determine, using a placebo-controlled, parallel design, whether right frontal rTMS
stimulation in patients with posttraumatic stress disorder leads to symptomatic improvement,
reductions in hemispheric regional blood flow, and improvements in ANS regulation. The
study hypothesis is that 1 Hz right frontal rTMS stimulation will be superior to sham
stimulation in reducing PTSD symptoms and physiology including improving abnormalities in
regional cerebral blood flow, vagal tone, and circulating hormone levels.
Subjects (age 18-70) meeting DSM-IV criteria for Posttraumatic Stress Disorder (PTSD).
Subjects will be individuals with chronic PTSD (i.e., greater than 1 year).
No subjects with evidence of uncontrolled significant medical illness on physical exam,
laboratory screening or EKG, presence of cardiac pacemakers, medication pumps, cochlear
implants, metal objects in the head or eyes, history of a seizure disorder, left
handedness, or pregnancy.
No subjects with unstable dissociative symptoms, current self-injurious behavior, current
eating disorder, active substance abuse (alcohol or illicit substance use within the past
three months), or active suicidality.
Subjects will be allowed to be on stable doses of benzodiazepines and/or antidepressants
while undergoing rTMS treatment.