Automatic and strategic processing in obsessive-compulsive disorder: attentional bias, cognitive avoidance or more complex phenomena?

Slowed color naming of threat-related words on the modified Stroop task has been interpreted as indicative of selective processing biases, although alternative models have been proposed to explain inconsistent findings. The present study compared the performance of participants with obsessive-compulsive disorder (OCD) and normal controls on a computerized version of the modified Stroop, and investigated the relationship of Stroop effects to avoidant cognitive strategies. Contrary to predictions, control and OCD groups were notably faster at color naming OCD threat, general threat, and positive words compared to neutral words at the strategic level of awareness. This was not the case for OCD threat words at the automatic level of awareness where faster color naming was observed, although the expected differences between groups were not found. A thought replacement measure was generally predictive of OCD participants' automatic pattern of interference for negatively valenced words. Results indicate the complexity of the Stroop effect and the need for its ongoing review.