Participants

Fifty-nine right-handed subjects who all experienced the same Wenchuan 8.0-magnitude earthquake were recruited (Table 1). The acquisition of neuroimaging and clinical data from survivors took place in December 2009, 17 months after this disaster. All participants were children or adolescents, who were between 8 and 18 years of age (35 PTSD with a mean age of 14.74 ± 2.08 years and 24 non-PTSD controls with a mean age of 14.58 ± 1.79 years) and didn’t suffer any physical head injury or any loss of consciousness > 5 min in the catastrophe. They were drawn from a large-scale PTSD survey of survivors 8–15 months after the earthquake. They were first carefully screened through the PTSD checklist (PCL) (32, 33). Subjects with a PCL score > 35 further participated in interviews led by two experienced psychiatrists. The Clinician-Administered PTSD Scale (CAPS) (34) was used to confirm the PTSD diagnosis in these individuals with suspected PTSD, and the structured clinical interview for DSM-IV (SCID) was used to exclude any psychiatric comorbidities. Those who scored > 50 on the CAPS were eligible for further evaluation for inclusion in the PTSD group. An age-and sex-matched trauma-exposed non-PTSD group was formed from those with a PCL score < 30 points and a CAPS score < 35 points. The exclusion criteria for the PTSD group were: (1) history of other nervous system diseases and psychiatric disorders; (2) use of psychotropic medications and drug treatment in the past 2 months; (3) any significant medical or history of head injury; (4) left-handedness; (5) IQ < 80; (6) magnetic resonance imaging contraindications. The traumatized control participants were similarly screened using the SCID and CAPS scale. These subjects who experienced the same traumatic events but with CAPS scores below 35 were included in the non-PTSD group. The non-PTSD control group used the same exclusion criteria as the PTSD group. An experienced neuroradiologist inspected brain scans and ruled out clinical abnormalities. This research was approved by the Medical Ethics Committee of West China Hospital, Sichuan University, and all subjects and their guardians offered written informed consent after being provided a complete description of this study.

Sample characteristics.^a

^aPresentation of characteristics is mean ± SD. ^bTwo-sample t-test was used to test continuous characteristics and categorical characteristics were tested by chi-square.