Sentence:  Apparently academic challenge in the structured setting creates an optimum of stress so that the child with high <WSD>anxiety</WSD> is able to achieve because he is aroused to an energetic state without becoming confused or panicked . 
Meaning of the word marked with <WSD> tags:  (psychiatry) a relatively permanent state of worry and nervousness occurring in a variety of mental disorders, usually accompanied by compulsive behavior or attacks of panic