Processing of Obsessive, Responsibility, Neutral Words and Pseudo-Words in Obsessive-Compulsive Disorder: A Study with Lexical Decision Test

Abstract

Twenty-four DSM-III-R non-depressed obsessive-compulsive (OCD) patients were compared to 21 normal subjects in three lexical decision experiments, to distinguish neutral, obsessive and responsibility words from pseudo-words. Error frequencies were comparable across groups. A significant taboo effect was found in both groups for obsessive and responsibility words. OCD patients did not differ from control subjects in their processing of neutral words and responsibility words. However, OCD patients were significantly slower than controls when processing obsessive words. Furthermore, OCD patients processed pseudo-words slower than controls if these were presented in the same experiment as obsessive words. When mixed with neutral or responsibility words, the performance of OCD patients with pseudo-words was similar to that of control subjects. The level of sub-clinical depression (as appreciated on the HAM-D scale) and psychotropic drugs (such as serotonin reuptake inhibitor) did not modify these results. Lexical decision performances were interpreted in terms of a cognitive disturbance triggered by obsessive stimuli that spreads to a neutral task. These results are compatible with the cognitive model of OCD (Salkovskis, 1985).