Of course other films have portrayed mental illness in that same age bracket - notably 1977's "I Never Promised You A Rose Garden" with Kathleen Quinlan as a teen schizophrenic - but this film's target audience has probably never even heard of that one.
The other inspiration was Bill Sackter, a close personal friend of Morrows that was the subject of an earlier television movie called Bill, (a role that won an Emmy and a Golden Globe for Mickey Rooney in 1981).