Thursday, May 24, 2012

Brain shrinkage in Japanese tsunami survivors with PTSD

Survivors of last year's Japanese tsunami who have PTSD from the disaster experienced a shrinking of their orbitofrontal cortex -- that's the part of the brain that is involved in decision-making and the regulation of emotion.

Brain shrinkage seen in Tohoku PTSD cases | The Japan Times Online

This is just the most recent evidence that shows PTSD is a very real, physical injury.


  1. One cannot tell from this whether the injury causes symptoms, or whether chemical changes from PTSD cause the shrinkage.

    My educated opinion is the latter sets up a negative feedback loop that makes those areas underused. Brain tissue that is not used shrinks (actually the neurons are affected).

    Shrinkage of the orbitofrontal cortex does not necessarily result in PTSD.


  2. Two problems with that opinion. First, not all cases of PTSD are accompanied by a TBI or other injury. Certainly there is a correlation with certain types of trauma, such as those experienced in combat, assault or MVAs. But long-term occupational stressors such as nurses, social workers and EMTs experience can also cause PTSD without an accompanying physical injury.
    Also, PTSD doesn't simply cause brain structures to become hypoactive. Some do (such as the hippocampus) but others, such as the mid anterior cingulate cortex and the amygdala actually become hyperactive after a trauma that results in the development of PTSD.
    I agree that it is probably chemical changes that result in the structural differences but it's not as simple as a negative feedback loop. There is also evidence that people naturally born with smaller hippocampuses are more likely to develop PTSD.