Els van Meijel

64 Chapter 4 | Results of a 2–4-year follow-up study The mean time between T1 and T2 was 32.9 months (SD = 6.6, range 22 to 49 months); the median was 33 months. In total, 54 boys (60%) and 36 girls (40%) participated at T2. Mean age of the children at T2 was 17.4 years (SD = 2.9, range 11 to 22 years). There were no significant differences between participants and non-participants with regard to age ( U = 2564, Z = −0.004, p = 0.99) or sex ( χ 2 = 0.064, p = 0.80). Follow-up participants reported significantly fewer posttraumatic stress symptoms at T1 than non-participants did ( U = 1809, Z = −2.628, p < 0.01). Measures Demographic information, type of accident, acute pain and trauma history Demographic information and information on the type of accident was obtained from the medical records shortly after the accident. Within two weeks after the accident, children reported the worst acute pain since the accident with the Visual Analogue Pain Scale (VAS). The VAS has a good reliability (intraclass correlation = 0.79), good correlation with the Faces Pain Scale-Revised scale ( r = 0.72) and strong correlation with the Colour Analogue Scale ( r = 0.92) (Le May et al., 2018). The VAS scores range from 0 to10 and can be classified as no or mild pain (0–3), moderate pain (4–7), and severe pain (8–10). See van Meijel et al. (2018) for full details of pain assessment and the VAS. Trauma history from before the accident was assessed at T1. Posttraumatic stress disorder At both T1 and T2, diagnostic interviews were conducted with both the parent and child to determine the severity of PTSD symptoms in the children. In the Netherlands, the Dutch version of the Anxiety Disorders Interview Schedule for DSM-IV—Child and Parent Version (ADIS-C/P) is used to diagnose PTSD in children (Siebelink & Treffers, 2001; Silverman & Albano, 1996). The ADIS-C/P is a commonly used diagnostic, semi- structured interview for the assessment of anxiety disorders—including PTSD—and mood and behavioral disorders in children aged 7–17 years. The ADIS-C/P has a good to excellent test–retest reliability for specific diagnoses ( κ = 0.61–1.00) (Silverman et al., 2001) and inter-rater reliability (Lyneham et al., 2007). Although the ADIS C/P was not designed for young adults 17–22 years old, we used this interview because it is child and parent informed and because it enabled us to compare T1 and T2 results