This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
Not a defence mechanism : 
Select and explain. 
A. Derailment, B. Represession, C. Distoion, D. Undoing
A: Derailment
Answer: A: Derailment 
Explanation: A i.e. Derailment Derailment is a disorder in thought. It is gradual or sudden detion in the train of thought without blocking, sometimes used synonymously with loosening of association. Defence mechanism of OCD are undoing, inhibition, displacement & reaction formation but not obsessionQ.