If a person does not have the ability to reason logically in high pressure situations (and is consequently always clueless), what term can be used to describe such a person? I'm looking for an adjective but a noun will also do.
If there is a medical term to describe such a condition I will be interested in knowing about that as well.
He sank into stormy contemplation, clueless how to handle the latest of his challenges.
So from the above example, such a person can be called a __________