The phrase "maddened by despair" refers to the state of being frustrated due to depression.
<u>EXPLANATION:</u>
Usage of the phrase maddened by despair in a sentence refers to the insane or frustrating behavior that a person makes when he is been subjected to grief and depression because of an incident.
<u>Example:</u>
Maddened by despair, the author wrote a novel that exhibited the pain and loneliness he underwent after the death of his daughter "the moment when I was aware of the sudden demise of my daughter, I would no longer wish to survive in this world". Here it expresses the grief of the author due to his daughter’s death.
