a1 Brain Dynamics Centre, Westmead Hospital, Sydney, NSW, Australia
a2 School of Psychology, University of New South Wales, Sydney, NSW, Australia
a3 Neuroscience Institute of Schizophrenia and Allied Disorders (NISAD), NSW, Australia
a4 Department of Radiology, Westmead Hospital, Sydney, NSW, Australia
Background Although cognitive behaviour therapy (CBT) is the treatment of choice for post-traumatic stress disorder (PTSD), approximately half of patients do not respond to CBT. No studies have investigated the capacity for neural responses during fear processing to predict treatment response in PTSD.
Method Functional magnetic resonance imaging (fMRI) responses of the brain were examined in individuals with PTSD (n=14). fMRI was examined in response to fearful and neutral facial expressions presented rapidly in a backwards masking paradigm adapted for a 1.5 T scanner. Patients then received eight sessions of CBT that comprised education, imaginal and in vivo exposure, and cognitive therapy. Treatment response was assessed 6 months after therapy completion.
Results Seven patients were treatment responders (defined as a reduction of 50% of pretreatment scores) and seven were non-responders. Poor improvement after treatment was associated with greater bilateral amygdala and ventral anterior cingulate activation in response to masked fearful faces.
Conclusions Excessive fear responses in response to fear-eliciting stimuli may be a key factor in limiting responses to CBT for PTSD. This excessive amygdala response to fear may reflect difficulty in managing anxiety reactions elicited during CBT, and this factor may limit optimal response to therapy.
(Received March 20 2007)
(Revised September 18 2007)
(Accepted October 11 2007)
(Online publication November 16 2007)