The reason you seldom hear of a celebrity having schizophrenia, is because of the nature of the illness. How many people with schizophrenia would be well enough to ever become a celebrity or movie star in the first place?
Schizophrenia in males is most likely to first present in late teens and twenties, though it can present much later. Women have a later presentation - even as late as their thirties, forties and fifties.
I worked with people who, prior to the onset of their illness, have been doctors, engineers, and so on.
I probably didn't explain myself well in my posts. My main points are that:
Psychiatric diagnosis is not a perfect science. It is common for a person with a serious mental illness like schizophrenia to have received a number of different diagnoses over the course of their illness - for a range of reasons. It is not uncommon for experts to disagree on diagnoses, and symptoms can change over time.
Different illnesses have different stereotypes. For schizophrenia, there are "axe murderer" and "Dr Jekyll /Mr Hyde stereotypes, amongst others. Even people with schizophrenia say this. From my extensive experience, the great majority of people with schizophrenia are decent people who constantly battle to the best of their ability with a very $hitty and, as yet, incurable illness. Medication can reduce psychoses, but the side effects can also be debilitating. IMO Bipolar is less stigmatised. Its stereotype is more likely to be creative, gregarious etc.
What has this got to do with OP?? I've almost forgotten... PTSD is one of the more socially acceptable psychiatric diagnoses and, like most, is difficult to "prove" or "disprove" definitively. This is particularly difficult when the diagnosis is based on the self-report of a person who has a strong vested interest in having such a diagnosis.