On a semantic negative priming task designed to investigate putative inhibitory mechanisms of selective attention, obsessive–compulsive disordered (OCD) subjects were distinguished from all other sub-categories of anxiety disorder (OAD). OCD subjects failed to show any priming effects in the repetition priming condition and exhibited facilitation in the semantic priming condition (i.e. shorter reaction times to previously ignored stimuli). OAD subjects demonstrated negative priming (i.e. longer reaction times to previously ignored stimuli) in both experimental conditions. These results are interpreted in terms of reduced cognitive inhibition in OCD and the implications of this hypothesis are discussed. Parallels are also drawn with previous studies regarding the results of high schizotypes and schizophrenic subjects using negative priming tasks.