What are some signs of mental illness

A sign of mental illness could be, self harm, isolation, sudden bursts of anger, change of attitudes (bipolar), etc.

Explanation:

precisely the author keeps the interest of readers not describing clearly the   kind of relationship in giselle's family. by doing this, readers had to imagine and assume how it was.   instead, the author described better scenes with dark star and the influence of books about horses in giselle's life and actions.   also the fact that she broke her arm but not referring to it in detail leads the readers to imagine and guess what could have occurred.