Are there any obvious signs that a parent should pay attention to?
Even the best parents would be hard-pressed to notice the changes immediately. It isn't like the child goes to bed one night and then wakes up the next morning changed.
Normally, parents might look back and say, "You know, the last couple months, so-and-so has been really withdrawn, staying in their room, not wanting to come and eat with us or spend time with us." But that can be normal, too, and that doesn't necessarily mean a person has schizophrenia.
Often, the symptoms that will be very evident would be what we call the positive symptoms. These include hallucinations, hearing things that aren't there, seeing things, feeling, smelling, tasting, something that's perceived through the senses that isn't there.Big clues include if the person just stops eating from things that they don't open themselves (such as milk containers), or if they talk about somebody trying to poison them. Schizophrenia is easier to discover when the clues are obvious.
Has the treatment of schizophrenia improved?
In the past, you couldn't get a psychiatrist to give a diagnosis of schizophrenia for a teenager, because it had such a negative connotation. Now, the paradigm has shifted and the emphasis is on early diagnosis and treatment. This can make a world of difference.