Physical pre-cursor for schizophrenia?

If schizonphrenia runs in your family, then that increases your chance of getting it, but doesnt mean that you will get it.
Also, taking recreational drugs can increase the chance of getting schizophrenia, especially if a person regularly takes lots of drugs at once, or any amount of drugs regularly over a long period of time.
If a person is experiencing any halucinations, or they think that they might be then i would recomend seeing a doctor as soon as possible to get some support, or just to talk about it.

Schizophrenia can be treated with drugs and therapy.

It is possible to have halucinations which are caused by taking recreational drugs. These halucinations should stop if the person stops taking the drugs. But if they are a heavy user of drugs, then the person should seek professional support (see a doctor) to assist in breaking the habbit.

Halucinations can be auditary (sounds), visual (seeing things), sensation or thoughts. The thoughts might be unusual or intrusive or overwhelming.

About precursors: there might be small or large changes in a persons behaviour or personality. A person might express opinions that are out of character. A person might be experiencing changes in their perception of the world around them, but they may or may not have much insight into any of these changes.

What a question. It is not enviromentally driven..more genetic/hereditary.

You will be hearing voices and hallucinating
I don't think that there are psychical pre-cursors, but there can definitely be actions that one can show. If they see things they may look around quickly a lot or if they hear things they may tug at their ears a lot or mumble to themselves. My aunt was Schizophrenic and those were some of her behaviors as well as some others I have come across.
Was the head of a Bi-Polar group for Houston for 2 years and also attended mood disorder gatherings.
There is none.
I'm a nurse
Most people regard the "diathesis stress model" playing a role in schizophrenia, (schz), this is an interaction of both environemental stresses, like disturbed family upbringing, abused background, with genetic causes, such as one of your parents having it.

there isnt a test to see if you have any predisposition to any particular mental illness incl. schz, i just say carry on as "normal" and not to worry, ca cera cera m'love