I didn't feel like the statement carried an implicit claim that no one has schizophrenia, or other cut-and-dry physical problems. Maybe I just read it that way, but I couldn't disagree more if that's what they meant.

I had a childhood friend who was diagnosed with schizophrenia and recently died from an over-dose of heroine. He was diagnosed in his late 20's, not sure when he started suffering, but I've wondered if he'd done better if he'd gotten help sooner.