What are the motifs in Wintergirls by Laurie Halse Anderson?

Friendship is a recurring idea in the story. Because Lia has closed herself off from the outside world, she has very few friends. The two friends that she has in the novel, Cassie and Elijah, both leave the reader questioning whether they were true friends to Lia or not. Lia and Cassie have been friends since they were in third grade, but when they were in sixth grade, that relationship started to change: Cassie began vomiting after eating and Lia began covering it up. As the years passed, both girls became obsessed with their eating disorders, dragging each other down into the dark depths of their depravity