Specificity of Stroop interference in patients with pain and PTSD.

The authors investigated processing of threat words in motor vehicle accident survivors using a modified Stroop procedure. Three samples were included: 28 participants with comorbid posttraumatic stress disorder (PTSD) and pain, 26 participants with pain without PTSD, and 21 participants without pain or any psychiatric conditions. Four word categories were used: (a) accident words, (b) pain words, (c) positive words, and (d) neutral words. This study examined whether processing biases would occur to accident words only in participants with PTSD or if these biases would also be noted in the No PTSD/Pain sample. Additionally, this study examined whether processing biases would be noted to pain words in the 2 pain samples, irrespective of PTSD. Overall, color naming was significantly slower in the PTSD/Pain group in comparison with the other groups. As well, the PTSD/Pain sample showed significant response delays to both accident and pain-related words, whereas patients with No PTSD/Pain showed delays to pain stimuli only.