Mental Illness
The most potent theme in this movie is that of mental illness. This is perhaps the first movie to confront the idea of mental illness the way that it does: the story is set in a time when mental illness was a silent epidemic, so no one could talk about it. Hence, it exposes the side of human psyche that people wished, and still wish, to ignore.
Identity
Girl, Interrupted is a story of a girls journey to explore her own identity and, hence, progress towards the goal of healing. While it might seem like a minor theme, the idea of identity is a significant one in this movie as it helps the narrator delineate the ups and downs that plague and antagonize her and hence explore her own reality.
Stigma
Another prominent theme is that of stigma. This story is a set in a time when homosexuality was a stigma, and this is just one of the elements that come through forcefully in the movie. It grapples with the idea of the peripheralization of those who suffer from a mental illness in the society.
Peer pressure
Peer pressure is another prominent theme in the movie. The protagonist is heavily influenced by the words and actions of Lisa, drawn to her for no clear reason. It is due to this influence that she resists medication and starts defying authorities, an act that leads to the suicide of Daisy.
