The neurobiological role of the dorsolateral prefrontal cortex in recovery from trauma. Longitudinal brain imaging study among survivors of the South Korean subway disaster.

CONTEXT A multiwave longitudinal neuroimaging study in a cohort of direct survivors of a South Korean subway disaster, most of whom recovered from posttraumatic stress disorder 5 years after trauma, provided a unique opportunity to investigate the brain correlates of recovery from a severe psychological trauma. OBJECTIVES To investigate region-specific brain mobilization during successful recovery from posttraumatic stress disorder by assessing cortical thickness multiple times from early after trauma to recovery, and to examine whether a brain-derived neurotrophic factor gene polymorphism was associated with this brain mobilization. DESIGN Five-year follow-up case-control study conducted from 2003-2007. SETTING Seoul National University and Hospital. PARTICIPANTS Thirty psychologically traumatized disaster survivors and 36 age- and sex-matched control group members recruited from the disaster registry and local community, respectively, who contributed 156 high-resolution brain magnetic resonance images during 3 waves of assessments. MAIN OUTCOME MEASURES Cerebral cortical thickness measured in high-resolution anatomic magnetic resonance images using a validated cortical thickness analysis tool and its prospective changes from early after trauma to recovery in trauma-exposed individuals and controls. RESULTS Trauma-exposed individuals had greater dorsolateral prefrontal cortical (DLPFC) thickness 1.42 years after trauma (right DLPFC, 5.4%; left superior frontal cortex, 5.8%; and left inferior frontal cortex, 5.3% [all clusters, P ≤ .01]) relative to controls. Thicknesses gradually normalized over time during recovery. We found a positive linear trend, with trauma-exposed individuals with a valine/valine genotype having the greatest DLPFC cortical thickness, followed by those with a methionine genotype and controls (P < .001 for trend). Greater DLPFC thickness was associated with greater posttraumatic stress disorder symptom reductions and better recovery. CONCLUSION The DLPFC region might play an important role in psychological recovery from a severely traumatic event in humans.