Usami, M., Iwadare, Y., Watanabe, K., et al. (2014). Decrease in the Traumatic Symptoms Observed in Child Survivors within Three Years of the 2011 Japan Earthquake and Tsunami. PLoS One. 9(10).
The authors studied in traumatic symptoms experienced by pediatric survivors of the 2011 Japan earthquake and tsunami 8, 20, and 30 months after the event. They found that while most negative effects decreased over time in this population, post-traumatic stress disorder and depressive symptoms did not improve consistently.