All the Bright Places explores mental illness primarily through the character of Theodore Finch, an adolescent boy who has bipolar disorder. Theodore’s family does not seek medical treatment for his illness, and at the novel’s end he dies by suicide. One of the novel’s key themes is that mental illness can lead to death if left untreated. In Theodore’s case, there are additional factors. His father is physically abusive, and several students at his school bully him.

In Jennifer Niven’s novel, Theodore’s tragic death results from a combination of factors and might have been prevented. The author contrasts his situation with that of a fellow student, Violet Markey. Violet is grieving for her late sister but apparently does not have an underlying medical condition. Violet moves through the grieving process and, though she had contemplated suicide, does not end her life.

The combined elements of family abuse and bullying exacerbate Theodore’s fragile state. An element of his disorder is his denying that he is ill. Without the needed family encouragement and intervention, the condition goes undiagnosed. Without this crucial step, he cannot receive treatment, which would likely include therapy and medication.