What is the theme in Next to Normal by Brian Yorkey?

Experiences of memory take place on several levels throughout the narrative - the loss of it, the search for it, the changeability of it, the feelings associated with it, the hidden truths associated with it, all come into play at one point or another. The character most obviously affected by the many shifting qualities of memory is Diana, whose life and existence are entirely haunted by the memory of her son and of his death. Her connection to that memory, and to the feelings associated with it, are so strong that she manifests an alternate, idealized, living version of her son, a means to escape or deny memory. Later, she realizes memory's importance and fights with everything she has to both rediscover it and honor it.