As Red calls him, Brooks is an "institutionalized man." The implication here is that Brooks entered Shawshank as a young man. His entire life was spent there. Red argued that "Life is what they took from him." Indeed, it is for this reason that Brooks is not able to make it on the outside. Inside prison, Brooks was respected, an "educated man." Yet, on the outside, he is simply seen "as an old, ex- con." It is for this reason that Brooks is challenged.
In a larger sense, Brooks represents what happens when hope leaves the individual. The lack of hope in Brooks' life is something that becomes evident when he is unable to cope with the different condition of life in the outside world. Brooks realizes that he was happier inside for there was a sense of predictability and control. These elements are absent in a world outside of Shawshank. Darabont, the writer of the film, makes it evident that it is this condition, one where daily consciousness has to be faced with a condition of hope, that makes life more bearable and makes life worth living. Without it, despair results, and the end consequence can be death.