The current article represents the further validation of the construct of inferential confusion amongst clinical samples. Inferential confusion is proposed to be a meta-cognitive confusion particularly relevant to obsessive compulsive disorder (OCD) that leads a person to confuse an imagined possibility with an actual probability. As such, it conceptualizes OCD as a form of belief disorder similar to a delusion or overvalued idea that is a product of distorted reasoning processes. In contrast, other cognitive models of OCD emphasize a phobic model of development in OCD, and thus consider the exaggerated interpretation of intrusions as an essential element in OCD. The present study administered a revised version of the Inferential Confusion Questionnaire, and the Obsessive Belief Questionnaire (OBQ), to a total of 183 participants in three clinical groups and a non-clinical control group. Results suggest that OCD, at least in part, follows a non-phobic model of development with inferential confusion significantly related to obsessive-compulsive symptoms independently of cognitive domains as measured by the OBQ, and mood states. Further, scores on inferential confusion were particularly high in those with OCD and delusional disorder as compared to anxious and non-clinical controls.