Reddit reviews Speak

Books About Mental Illness:

• January First, nonfiction about childhood schizophrenia from the father's perspective
  
• Speak, about a high school freshman who develops selective mutism in order to deal with trauma
  
• Wintergirls, about eating disorders and a girl who keeps seeing her dead best friend
  
• The Perks of Being a Wallflower, about a freshman with older party animal friends and PTSD
  
• Slaughterhouse Five, where the main character develops PTSD after being involved in the bombing of Dresden, but thinks he's become unstuck in time, abducted by aliens, etc.
  
• The Curious Incident of the Dog in the Night-Time, about an autistic teenager who tries to solve a mystery with his own brand of logic

I just saw a recommendation for a book called Speak and sent a Kindle sample to my friend to have a look for her nieces.