Emotional stress over last year’s deadly quake and tsunami in the Tohoku region caused the brains of some survivors to shrink, according to scientists in Japan who had a unique chance to study the neurological effects of trauma.
On a quest to better understand posttraumatic stress disorder, the researchers compared brain scans they had taken of 42 healthy adolescents in other studies in the two years before the disasters new images taken three to four months after they hit.
Among those with PTSD symptoms, they found a shrinking in the orbitofrontal cortex, a part of the brain involved in decision-making and the regulation of emotion, according to a study published Tuesday in Molecular Psychiatry, a branch of Nature.
“The changed volumes in the orbitofrontal cortex are correlated to the severity of PTSD symptoms,” author Atsushi Sekiguchi said.
Previous studies had already suggested PTSD patients experienced changes to the brain, but this is the first to pinpoint which part of the organ is altered by trauma.
The full implications of the findings are so far unclear, but there could be an early benefit for doctors and patients. Telltale changes in brain volume may help in diagnosing PTSD and expedite treatment with psychotherapy.
The researchers also found that people with a smaller anterior cingulate cortex before a traumatic event were more prone to develop PTSD.
This part of the brain is also believed to be involved in decision-making and emotion.
“We think these changes are not permanent, because many past studies showed that brain changes were recovered by some therapies or interventions,” said Sekiguchi. “To confirm this, we have already started to follow up the subjects.”
None of the 42 subjects have been diagnosed with full-blown PTSD, but they have displayed symptoms of varying severity.
Symptoms of PTSD, a severe form of depression, include flashbacks, emotional numbness, sleepnessness and hypervigilance.
Sekiguchi, from Tokohu University’s department of functional brain imaging, conceded the sample size was small but insisted “there is some mathematical validity to generalize to a broad population from our data.”
The subjects all lived in an inland area of the quake-ravaged city of Sendai.
“Not only the earthquake itself, but also frequent aftershocks, radioactive materials leaked from nuclear (reactors), and many inconveniences after the quake, such as shut-off utilities, caused stressful periods” for the subjects, the scientist said.
Some 19,000 people died when the magnitude-9.0 Great East Japan Earthquake struck off the Tohoku coast on March 11, 2011, triggering massive tsunami, followed by three reactor meltdowns at the Fukushima No. 1 nuclear plant.
“This extremely miserable episode provided a rare opportunity for investigating brain structural changes associated with such a disaster,” the authors wrote.