nbc's raheem ellis reports on the warning signs that every parent should be looking for. >> 15-year-olk killian battled depression since she was a little girl. >> when she was 9 she threatened suicide. >> last year she made another attempt, taking an overdose of pills but reached out to her parents for help. >> every day i'm so grateful that she did. >> i don't want to leave my siblings without -- >> disturbing new numbers from the cdc shows too many teenagers are not getting the help they need, especially girls aged 15 to 19. the rate of suicide for girls has doubled. cases jumping from 260 to 524 in eight years. for boys, the rate jumped 31%. >> parents will be looking and saying, what can i do? >> the first thing parents can do is to become knowledgeable about mental health. >> experts say there's no single cause, but point to the overwhelming prevalence of social media and cyber bullying as factors. and depictions of teenage series, 13 reasons why. a tv drama about a high school girl who killed herself. >> everyone's lives would be better without me. >> have coincided with an incre