UCLA researchers have studied survivors of catastrophes and they have concluded that a "vulnerability to PTSD, anxiety and depression" seems to clearly run in families.  The study looked at 200 participants from 12 multigenerational families that were exposed to serious earthquakes.  The study participants at the time of observation suffered from varying degrees of the 3 disorders.  It was first observed that the 3 disorders had shared genetic liabilities, meaning you were at risk for more than one of these 3. 

The study specifically observed that:

- 41% of the PTSD symptoms was due to shared genetic tendencies

-  61% of the depressive symptoms were attributed to genetics

- 66% of the anxiety symptoms were attributed to a genetic link

Since any catastrophe, earthquake included, can cause PTSD, anxiety or depression - or a combination of these - knowing that there is an inheritable aspect to these conditions, could help families (and their healthcare providers) be aware of the tendency and allow for early recognition and intervention.  These studies also takes a big step in corroborating what was seen in twin studies involving these issues.  The earthquake catastrophe also helps to look at a condition, PTSD, that more typically affects an individual, like a soldier - in the context of family predisposition.

This study is expected to fuel further research into the genetic connection and the underlying biology of these 3 conditions.