In his addiction, he destroys the trust of everyone around him and erodes his life into nothing but desperation. He would steal from his family and work the streets to support his habits. Though that is not an unusual tale for substance abusers, Sheff is also diagnosed with bipolar disorder. Further, it is not until he recognizes his own self-hate and past trauma that he is able to move forward and have a more successful, sincere attempt at living independently sober. Alternative therapies at the rehabilitation center near the end of the novel help him do this.
If you prefer to have a vicarious speed experience, this is a good novel.