A patient was recently diagnosed with a terminal illness. The patient exhibits little emotion about the diagnosis but spends hours researching the illness. Which defense mechanism are they likely using?

The patient’s behavior of researching the illness while showing minimal emotional response indicates the use of intellectualization as a defense mechanism. Intellectualization involves separating one's emotions from a stressful event by focusing on the intellectual aspects related to it. Instead of confronting the emotional weight of a terminal diagnosis, the patient is engaging in the cognitive process of gathering information and understanding the illness. This allows them to cope with the situation in a more detached manner, maintaining a sense of control over something that feels overwhelmingly threatening.

In this context, other defense mechanisms would manifest differently. Regression involves reverting to earlier stages of development, while projection entails attributing one's thoughts or feelings onto someone else. Displacement would involve shifting emotional responses from the original source of distress to another object or person. The patient’s focused research aligns specifically with intellectualization, making it the most fitting choice in understanding how they are coping with their diagnosis.