Rather than describing the plot of the film, I want to focus on the issues at the heart of the film. Particular scenes reveal the loneliness of the two siblings. A single shot of Brandon running through the streets of New York at night in an attempt to flee from his sister's activities in his flat, is a beautiful portrayal of a man's quest for escapism.
One of the extras on the DVD is an interview with Michael Fassbender in which he talks about how he researched the character and met with sex addicts to get an insight into their situation. Fassbender comments that there was one particular addict that he learned a lot from. He remarked that rather than probe with questions in an order to be able to 'use' the material for his own gain, he tried to encourage the addict simply to tell his story. I have also found that once people are invited to tell stories, they are more open and relaxed, giving more honest and genuine responses.
There is an argument that one cannot understand how it feels to be in a particular situation e.g. be an addict, until one has a direct experience of the situation. Although I tend to agree with this, I do think it is important to have access to artforms (films, literature, art, theatre etc) that portray such situations and conditions. It is through films like Shame that people are given an insight into the complexities of things they may not otherwise witness or experience.