We read with great interest the article by Brewin et al (Reference Brewin, Rose and Andrews2002). The authors examined the efficiency of the 10-item version of the Trauma Screening Questionnaire (TSQ) in detecting post-traumatic stress disorder (PTSD). In our opinion, the scale design has some limitations which may have a negative influence on its practical application.

First, the TSQ contains five re-experiencing items and five arousal items, but not the avoidance and numbing symptoms. According to DSM-IV diagnostic criteria for PTSD (American Psychiatric Association, 1994), the patient requires the presence of at least one re-experiencing symptom (criterion B), three avoidance symptoms (criterion C), and two arousal symptoms (criterion D). The criterion C is the least frequently met criterion but critically significant to the diagnosis of PTSD (Reference Maes, Delmeire and SchotteMaes et al, 1998). Some trauma survivors, who express most PTSD symptoms, do not fulfil the avoidance criterion and are diagnosed as having ‘partial’ PTSD. Other briefer screening instruments, such as the four-item SPAN (Reference Meltzer-Brody, Churchill and DavidsonMeltzer-Brody et al, 1999) or the seven-item scale by Breslau et al (Reference Breslau, Peterson and Kessler1999), place much weight on the avoidance and numbing symptoms. Therefore, this specific item composition may influence the efficiency of the TSQ.

Second, the TSQ uses the frequency threshold allied to a ‘yes/no’ response format. Although comparison of scores derived by frequency and by severity indicated a degree of similarity, the severity dimension might provide better discrimination than the frequency dimension (Reference Meltzer-Brody, Churchill and DavidsonMeltzer-Brody et al, 1999). In our clinical experience, subjects can score the severity variable more accurately than the frequency ones (Reference Chen, Lin and TangChen et al, 2001). The item selection and scoring method have greater influence on the efficacy of the rating scale.