Background: On December 26, 2004, the tsunami destroyed many families, communities, and residential areas. Adverse psychological impact on children and adolescents due to a natural disaster of this magnitude has never been reported in Thailand’s history particularly as Post-Traumatic Stress Disorder (PTSD).
Objective: Investigate clinical symptoms and develop a 2-year monitoring and intervention program for PTSD in children affected by the December 26, 2004 tsunami natural disaster. The study period started six weeks after the event and was completed after two years.
Material and Method: One thousand six hundred and twenty five surviving students from two schools in Takuapa district, Phang-nga Province, were enrolled. Screening tests using Pediatric symptom checklists, Childhood depressive intervention (CDI), and Revised child impact of events scales (CRIES) were done. Psychiatric evaluations were done by child and adolescent psychiatrists. Post Traumatic Stress Disorder (PTSD) was diagnosed using criteria from Diagnostic and Statistical Manual of Mental Disorders, 4th edition.
Results: The prevalence of PSTD in the affected students were 57.3, 46.1, 31.6, 10.4, and 7.6% at 6 weeks, 6 months, 1 year, 1 years, and 2 years, respectively. The female: male ratio was 1.7:1. The peak age was 9-10 years old. Threatened situations were studied. Of the 176 students who risked their lives in the waves, 48 (27.3%) suffered from PTSD. Meanwhile, of the 1,314 students who were not hit by the waves but were among affected friends and relatives, 42 students (3.1%) suffered from PTSD. The prevalence of PTSD in those hit by the waves were significantly higher than those who were not [p-value < 0.01, RR = 5.16 (4.04-.6.6)].
Conclusion: The prevalence of PSTD in children who suffered from the tsunami disaster was as high as 57.3% at six weeks after the incident. It declined sharply at two years (7.6%) with the help of integrated welfare. The children continue to get financial, rehabilitation, and mental health support to prevent long-term adverse outcomes.

Keywords: Tsunami in Thailand, Post-Traumatic Stress Disorder (PTSD)