Els van Meijel

65 Results of a 2–4-year follow-up study | Chapter 4 more effectively. Cronbach’s alphas were 0.84 for the child score and 0.77 for the parent score. Depending on the answer and the clinical interpretation of the interviewer, symptoms can be rated as present or absent. If the number of symptoms endorsed as ‘yes’ is enough to meet DSM-IV-TR PTSD criteria (APA, 2000), impairment in daily functioning is rated on a 9-point Likert scale (0–8). A diagnosis of PTSD requires an impairment level of 4 or more and depends also on the clinician’s judgment of clinical severity. The diagnosis can be based upon either the child report (C) or the parent report (P), or a combination of both reports. Partial PTSD is diagnosed when at least one symptom is present in each of three subscales – re-experiencing, avoidance and hyperarousal – resulting in substantial distress or impairment in one or more areas of functioning (Winston et al., 2003). The PTSDmodule of the ADIS C/P was administered with regard to the accident. If indicated it was also administered with regard to any new traumatic event that had happened between T1 and T2. In the present study, PTSD refers to diagnosed PTSD, including diagnosed partial PTSD. Clinically significant self-reported posttraumatic stress (PTSS) At T1, children completed the Dutch version of the Children’s Revised Impact of Event Scale (CRIES; Children and War Foundation, 1998; Olff, 2005; Verlinden et al., 2014). This self-report measure gives a good indication of the presence of PTSD. It consists of 13 questions in the subscales re-experiencing, avoidance and hyperarousal, with answers on a 4-point scale. Items are rated according to the frequency of their occurrence during the past week (not at all=0, rarely=1, sometimes=3 and often=5; range 0–65). We asked the children to focus on their accident when answering the questions. The cut-off score for a positive test is 30 (Verlinden et al., 2014). The outcome correlates highly with the PTSD diagnosis according to the Anxiety Disorders Interview Schedule for DSM-IV, Child and Parent Version (ADIS C/P) (Verlinden et al., 2014). The CRIES has excellent test–retest reliability ( κ = 0.85) and good reliability (Cronbach’s alpha = 0.89) (Verlinden et al., 2014). For the current sample Cronbach’s alpha = 0.91. At T2, we used two self-report measures: one for children under 18 and one for children 18 years and older. The children under 18 completed the CRIES (see T1 above) and children 18 years and older completed the Dutch version of the Impact of Event Scale-Revised (IES-R; Horowitz et al., 1979; Weiss, 2007). The IES-R consists of 22