Cognitive models of obsessive-compulsive disorder attribute a causal role to maladaptive beliefs.

To test this hypothesis, we manipulated Overimportance of Thoughts (OT) beliefs and experimentally evaluated their effect on the response to an induced aggressive impulse.

Eighty-five participants completed a battery of self-report instruments assessing obsession symptoms, thought control, affectivity and obsessive beliefs, and were then randomly assigned to two conditions. In the experimental condition participants read a scientific abstract on the importance of thought control whilst those in the control condition read a neutral abstract. All participants identified a loved person and imagined feeling the impulse to stab this person, then completed again OT beliefs measures (Overimportance of Thought, Moral-Thought Action Fusion and Thought Action Fusion Likelihood).

The Moral component of the Thought Action Fusion was reduced by reading a brief text about the possibility and desirability of thought control. However, experimentally induced changes in beliefs did not yield differences in the intrusiveness of the aggressive impulse.

Some beliefs can be modified through a single session in which information similar to what could be obtained in quotidian life is provided.