EFFECTS OF VARYING SCORING RULES OF THE CLINICIAN-ADMINISTERED PTSD SCALE (CAPS) FOR THE DIAGNOSIS OF POSTTRAUMATIC-STRESS-DISORDER IN MOTOR-VEHICLE ACCIDENT VICTIMS

We examined the effects of varying the scoring rules for the CAPS (Cli nician Administered PTSD Scale) on the diagnosis of PTSD in a sample o f 100 victims of recent motor vehicle accidents. This was done by asse ssing, for each scoring rule, the rate of categorical diagnosis and th e effect on group mean scores on measures of subjective distress and r ole impairment. Changing from the most liberal to the most conservativ e scoring rule results in a change in diagnosis of PTSD from 44% to 29 % of the sample. Comparisons of those included as PTSD under the most conservative scoring criteria vs those excluded (who had previously be en included) reveal significantly greater subjective distress and role impairment among those who continue to be included in the PTSD catego ry. Thus, changes in scoring rules have clinically significant effects on the incidence and severity of diagnosed PTSD. This indicates that the selection of scoring rules has important implications for epidemio logical estimates of the prevalence of PTSD, and that PTSD studies usi ng different scoring rules as inclusion criteria may be using somewhat different samples.